U.S. patent application number 11/833581 was filed with the patent office on 2009-02-05 for systems and methods for providing iip address stickiness in an ssl vpn session failover environment.
Invention is credited to Saibal Adhya, Akshat Choudhary, Arkesh Kumar, Amarnath Mullick, Shashi Nanjundaswamy, Sergey Verzunov.
Application Number | 20090037763 11/833581 |
Document ID | / |
Family ID | 40339279 |
Filed Date | 2009-02-05 |
United States Patent
Application |
20090037763 |
Kind Code |
A1 |
Adhya; Saibal ; et
al. |
February 5, 2009 |
Systems and Methods for Providing IIP Address Stickiness in an SSL
VPN Session Failover Environment
Abstract
The SSL VPN session failover solution of the appliance and/or
client agent described herein provides an environment for handling
IP address assignment and end point re-authorization upon failover.
The appliances may be deployed to provide a session failover
environment in which a second appliance is a backup to a first
appliance when a failover condition is detected, such as failure in
operation of the first appliance. The backup appliance takes over
responsibility for SSL VPN sessions provided by the first
appliance. In the failover environment, the first appliance
propagates SSL VPN session information including user IP address
assignment and end point authorization information to the backup
appliance. The backup appliance maintains this information. Upon
detection of failover of the first appliance, the backup appliance
activates the transferred SSL VPN session and maintains the user
assigned IP addresses. The backup appliance may also re-authorize
the client for the transferred SSL VPN session.
Inventors: |
Adhya; Saibal; (Bangalore,
IN) ; Choudhary; Akshat; (Bangalore, IN) ;
Nanjundaswamy; Shashi; (Bangalore, IN) ; Verzunov;
Sergey; (Moscow, RU) ; Kumar; Arkesh; (Santa
Clara, CA) ; Mullick; Amarnath; (Bangalore,
IN) |
Correspondence
Address: |
CHOATE, HALL & STEWART / CITRIX SYSTEMS, INC.
TWO INTERNATIONAL PLACE
BOSTON
MA
02110
US
|
Family ID: |
40339279 |
Appl. No.: |
11/833581 |
Filed: |
August 3, 2007 |
Current U.S.
Class: |
714/4.12 ;
714/E11.023 |
Current CPC
Class: |
H04L 63/166 20130101;
H04L 12/4641 20130101; H04L 29/12216 20130101; H04L 61/2007
20130101; H04L 63/0272 20130101; H04L 69/40 20130101; H04L 67/14
20130101 |
Class at
Publication: |
714/4 ;
714/E11.023 |
International
Class: |
G06F 11/07 20060101
G06F011/07 |
Claims
1. A method of maintaining a user's intranet internet protocol
address upon failover of a client's secure socket layer virtual
private network (SSL VPN) session from a first appliance to a
second appliance, the method comprising the steps of: (a)
receiving, by a second appliance, information from a first
appliance, the information identifying one or more intranet
internet protocol addresses assigned to a first user for accessing
a network via a first secure socket layer virtual private network
(SSL VPN) session provided by the first appliance; (b) detecting,
by the second appliance, the first appliance is unavailable to
provide the first SSL VPN session to the network; (c) receiving, by
the second appliance, a request from the client operated by the
first user to establish a second SSL VPN session with the network;
and (d) assigning, by the second appliance, to the client a first
intranet internet protocol address previously assigned to the first
user from the one or more intranet internet protocol addresses as
an internet protocol address on the network.
2. The method of claim 1, wherein step (b) comprises providing, by
the second appliance, SSL VPN connectivity to the network in
response to the detection.
3. The method of claim 1, wherein step (d) comprises assigning, by
the second appliance, one of a least recently or a most recently
used intranet internet protocol address of the one or more intranet
internet protocol addresses as the first intranet internet protocol
address.
4. The method of claim 1, wherein step (d) comprises assigning, by
the second appliance, one of a least used or a most used intranet
internet protocol address of the one or more intranet internet
protocol addresses as the first intranet internet protocol
address.
5. The method of claim 1, wherein step (d) comprises assigning, by
the second appliance, the first intranet internet protocol address
from the one or more intranet internet protocol addresses
responsive to a policy of a policy engine.
6. The method of claim 1, wherein step (d) comprises determining,
by the second appliance, an inactive intranet internet protocol
address from the plurality of multiple intranet internet protocol
addresses as the first intranet internet protocol address.
7. The method of claim 1, comprising identifying, by the second
appliance, a policy specifying a domain name suffix to append to an
identifier of the user to provide a user domain name.
8. The method of claim 7, comprising associating, by the second
appliance, the user domain name with the first intranet internet
protocol address.
9. The method of claim 1, wherein step (c) comprises receiving, by
the second appliance, one or more client-side attributes of the
client.
10. The method of claim 9, comprising assigning, by the second
appliance, the client to an authorization group based on the one or
more client-side attributes.
11. The method of claim 1, wherein step (c) comprises transmitting,
by the second appliance, a request to the client to evaluate at
least one clause of the security string, the at least one clause
including an expression associated with a client-side
attribute.
12. The method of claim 11, comprising receiving, by the second
appliance, a result of the client's evaluation of the at least one
clause, and assigning, by the second appliance, the client to an
authorization group based on the result.
13. A system for maintaining a user's intranet internet protocol
address upon failover of a client's secure socket layer virtual
private network (SSL VPN) session from a first appliance to a
second appliance, the system comprising the steps of: means for
receiving by a second appliance information from a first appliance,
the information identifying one or more intranet internet protocol
addresses assigned to a first user for accessing a network via a
first secure socket layer virtual private network (SSL VPN) session
provided by the first appliance; means for detecting by the second
appliance the first appliance is unavailable to provide the first
SSL VPN session to the network; means for receiving by the second
appliance a request from the client operated by the first user to
establish a second SSL VPN session with the network; and means for
assigning by the second appliance to the client a first intranet
internet protocol address previously assigned to the first user
from the one or more intranet internet protocol addresses as an
internet protocol address on the network.
14. The system of claim 13, wherein the second appliance provides
SSL VPN connectivity to the network in response to the
detection.
15. The system of claim 13, wherein the second appliance assigns
one of a least recently or a most recently used intranet internet
protocol address of the one or more intranet internet protocol
addresses as the first intranet internet protocol address.
16. The system of claim 13, wherein the second appliance assigns
one of a least used or a most used intranet internet protocol
address of the one or more intranet internet protocol addresses as
the first intranet internet protocol address.
17. The system of claim 13, wherein the second appliance assigns
the first intranet internet protocol address from the one or more
intranet internet protocol addresses responsive to a policy of a
policy engine.
18. The system of claim 13, wherein the second appliance determines
an inactive intranet internet protocol address from the plurality
of multiple intranet internet protocol addresses as the first
intranet internet protocol address.
19. The system of claim 13, wherein the second appliance identifies
a policy specifying a domain name suffix to append to an identifier
of the user to provide a user domain name.
20. The system of claim 19, wherein the second appliance associates
the user domain name with the first intranet internet protocol
address.
21. The system of claim 13, wherein the second appliance receives
one or more client-side attributes of the client.
22. The system of claim 21, wherein the second appliance assigns
the client to an authorization group based on the one or more
client-side attributes.
23. The system of claim 13, wherein the second appliance transmits
a request to the client to evaluate at least one clause of the
security string, the at least one clause including an expression
associated with a client-side attribute.
24. The system of claim 13, wherein the second appliance receives a
result of the client's evaluation of the at least one clause, and
assigns the client to an authorization group based on the result.
Description
FIELD OF THE INVENTION
[0001] The present invention generally relates to data
communication networks and, in particular, to systems and methods
for performing SSL VPN session failover.
BACKGROUND OF THE INVENTION
[0002] A typical computer system uses a single internet protocol
(IP) address assigned to the computer system. Any user session or
program on the computer will use the IP address of the computer for
network communications on a TCP/IP network. Communications over the
network to and from the computer, for example between a client and
a server, use the computer's IP address as part of the network
communications of the computer. In a virtual private network
environment, a remote user may establish a virtual private network
connection from a client to a second network, such as via an SSL
VPN connection from a client on a public network to a server on a
private network. On the second network, a second IP address is used
for communications between the client and the server.
[0003] A user of the virtual private network may log in via the
same computing device or roam between computing devices. For each
login session, a different second IP address may be used for
virtual private network communications. Also, for each computing
device of the user, a different second IP address may be used for
virtual private network communications. As such, the user and/or
computing device of the user may be associated with different IP
addresses on the virtual private network at various times. In some
cases, the user may have multiple virtual private network sessions
concurrently, and thus, multiple IP addresses on the private
network. Identifying, tracking or managing the virtual private
network addresses of remote users is challenging, and may be
compounded in an environment with a multitude of remote virtual
private network users.
[0004] One challenge with assigning IP addresses for users of a
virtual private network is handling failures with devices providing
the IP address. A first device, such as a gateway, may assign the
user a first IP address for use on a private network. The first
device may experience a failure. The user may need to gain access
to the private network via a second device, such as a second
gateway. This second device may assign the user a second IP address
for use on the private network. This may cause problems in
communications with the private network as the client, applications
and/or a server may expect the user to be using the first IP
address.
[0005] Another challenge with failovers in a virtual private
network environment is security. A gateway device providing VPN
connectivity may authorize a client to access the network. The
gateway may check if the client device has attributes meeting one
or more conditions for accessing the network. For example, the
gateway may check if the client has security software installed or
the appropriate operating system patch. Upon authorization, a user
may access the private network via the gateway such as via a SSL
VPN session. At some point, the gateway may fail or operation may
be interrupted. The client may re-establish the SSL VPN session
with the network. However, the attributes of the client upon which
the client was authorized may have changed since establishing the
session. For example, security software or operating system patches
on the device may have been installed or removed. This may leave
the network vulnerable to these changes when re-establishing
sessions with previously authorized clients.
BRIEF SUMMARY OF THE INVENTION
[0006] The SSL VPN session failover solution of the appliance
and/or client agent described herein provides an environment for
handling IP address assignment and end point re-authorization upon
failover. The appliances may be deployed to provide a session
failover environment in which a second appliance is a backup to a
first appliance when a failover condition is detected, such as
failure in operation of the first appliance. The backup appliance
takes over responsibility for SSL VPN sessions provided by the
first appliance. In a failover environment, the first appliance
propagates SSL VPN session information including user IP address
assignment and end point authorization information to the backup
appliance. The backup appliance maintains this information. Upon
detection of failover of the first appliance, the backup appliance
activates the transferred SSL VPN session and maintains the user
assigned IP addresses. The backup appliance may also re-authorize
the client for the transferred SSL VPN session.
[0007] In one case, the appliance provides techniques and policies
for assigning previously assigned virtual private network
addresses, referred to as Intranet IP (IIP) addresses, of a user to
subsequent sessions of the user as the user logs in multiple times
or roams between access points. This technique is referred to IIP
stickiness as the appliance attempts to provide the same IIP
address to a reconnecting VPN user. In the case of appliance
failover, in which a backup appliance takes over responsibility for
a user's SSL VPN session, the appliances provide seamless IIP
address stickiness for the user as the SSL VPN session is
transferred to the backup appliance. The user continues his or her
SSL VPN session with the backup appliance using one of the
previously assigned IIP addresses of the user.
[0008] In another case, the appliance provides for end point
detection and re-authorization of the client upon transfer of a
user's SSL VPN session from a first appliance to a backup
appliance. The appliance provides techniques for performing end
point detection and authorization using policy-based client
security strings to determine attributes of the client device.
Depending on the values and evaluation of these client security
strings, the appliance may authorize the client to access the
virtual private network in accordance with one or more policies. An
authorized client may establish an SSL VPN session with the first
appliance. The first appliance may experience a failover condition
and the SSL VPN session is transferred to a backup appliance.
Although the client was authorized by the first appliance for the
SSL VPN session, the backup appliance performs end point detection
and re-authorization client for the transferred SSL VPN session
using the client security string.
[0009] In some aspects the present invention relates to a system
and method of maintaining a user's intranet internet protocol
address upon failover of a client's secure socket layer virtual
private network (SSL VPN) session from a first appliance to a
second appliance. A second appliance receives information from a
first appliance. The information identifies one or more intranet
internet protocol (IIP) addresses assigned to a first user for
accessing a network via a first secure socket layer virtual private
network (SSL VPN) session provided by the first appliance. The
second appliance detects the first appliance is unavailable to
provide the first SSL VPN session to the network The second
appliance receives a request from the client operated by the first
user to establish a second SSL VPN session with the network. The
second appliance assigns to the client a first intranet internet
protocol address previously assigned to the first user from the one
or more intranet internet protocol addresses as an internet
protocol address on the network.
[0010] In one embodiment, the second appliance provides SSL VPN
connectivity to the network in response to the detection. In
another embodiment, the second appliance assigns a least recently
or a most recently used intranet internet protocol address of the
one or more intranet internet protocol addresses as the first
intranet internet protocol address. In some embodiments, the second
appliance assigns a least used or a most used intranet internet
protocol address of the one or more intranet internet protocol
addresses as the first intranet internet protocol address. In
another embodiment, the second appliance assigns the first intranet
internet protocol address from the one or more intranet internet
protocol addresses responsive to a policy of a policy engine.
[0011] In other embodiments, the second appliance determines an
inactive intranet internet protocol address from the plurality of
intranet internet protocol addresses as the first intranet internet
protocol address. In one embodiment, the second appliance
identifies a policy specifying a domain name suffix to append to an
identifier of the user to provide a user domain name. In some
embodiments, the second appliance associates the user domain name
with the first intranet internet protocol address.
[0012] In some embodiments, the second appliance receives one or
more client-side attributes of the client, such as via end point
detection. For example, the second appliance may transmit a request
to the client to evaluate at least one clause of a security string.
The clause may include an expression associated with a client-side
attribute. The second appliance may receive a result of the
client's evaluation of the at least one clause. The second
appliance assigns the client to an authorization group based on the
one or more client-side attributes.
[0013] In other aspects, the present invention relates to a system
and method of performing authorization of a client's secure socket
layer virtual private network (SSL VPN) session transferred upon
failover from a first appliance to a second appliance. The second
appliance receives from the first appliance, information
identifying a security string used by the first appliance to
authorize a secure socket layer virtual private network (SSL VPN)
session established between a client and a network. The second
appliance detects the first appliance is unavailable to continue
the SSL VPN session. The second appliance provides the SSL VPN
session for the client in response to the detection. The second
appliance places the SSL VPN session on hold until the client is
authorized by the second appliance. The t second appliance
transmits a request to the client to evaluate at least one clause
of the security string. The at least one clause includes an
expression identifying a client-side attribute.
[0014] In one embodiment, the second appliance activates the on
hold SSL VPN session upon receiving a predetermined result from
evaluation of the least one clause of the security string. In
another embodiment, the second appliance assigns the client to an
authorization group based on a result from evaluation of the at
least one clause. In some embodiments, the second appliance
transmits the request to a collection agent on the client. The
collection agent gathers information associated with the
client-side attribute and evaluates the at least one clause. In
other embodiments, the second appliance receives from the client in
response to the request a result from evaluation of the at least
one clause providing the client-side attribute.
[0015] The client side attribute may indicate a presence on the
client of any of the following: a version of an operating system, a
service pack of the operating system, a running service, a running
process, and a file. The client-side attribute may also indicate a
presence on the client of any one or more of the following:
antivirus software, personal firewall software, anti-spam software,
and internet security software.
[0016] In some embodiments, the second appliance, responsive to a
result from evaluation of the at least one clause, determines that
the client lacks a desired client-side attribute. In response to
the determination the second appliance may maintain the SSL VPN
session on hold. The second appliance may determining from a result
from evaluation of the at least one clause that the client-side
attribute is not set to a value in accordance with a policy. The
second appliance may continue to keep the SSL VPN session on hold
in response to the determination.
[0017] In another embodiment, the second appliance assigns the
client to an authorization group providing quarantined access to
the network in response to a result from evaluation of the at least
one clause. The second appliance then may activate the SSL VPN
session. In other embodiments, the second appliance assigns the
client to an authorization group responsive to an application of a
policy by a policy engine to a result from evaluation of the at
least one clause, and then may activate the SSL VPN session.
[0018] The details of various embodiments of the invention are set
forth in the accompanying drawings and the description below.
BRIEF DESCRIPTION OF THE FIGURES
[0019] The foregoing and other objects, aspects, features, and
advantages of the invention will become more apparent and better
understood by referring to the following description taken in
conjunction with the accompanying drawings, in which:
[0020] FIG. 1A is a block diagram of an embodiment of a network
environment for a client to access a server via an appliance;
[0021] FIG. 1B is a block diagram of an embodiment of an
environment for delivering a computing environment from a server to
a client via an appliance;
[0022] FIGS. 1C and 1D are block diagrams of embodiments of a
computing device;
[0023] FIG. 2A is a block diagram of an embodiment of an appliance
for processing communications between a client and a server;
[0024] FIG. 2B is a block diagram of another embodiment of an
appliance for optimizing, accelerating, load-balancing and routing
communications between a client and a server;
[0025] FIG. 3 is a block diagram of an embodiment of a client for
communicating with a server via the appliance;
[0026] FIG. 4 is a block diagram of an embodiment of an appliance
and client providing an Intranet Internet Protocol (IIP)
environment;
[0027] FIG. 5 is a flow diagram depicting steps of an embodiment of
a method for practicing a technique for assigning an IIP address to
a user;
[0028] FIG. 6A is a block diagram of an embodiment of a network
environment providing policy-based access to application programs
for a local machine;
[0029] FIG. 6B is a block diagram depicting a more detailed
embodiment of a policy engine;
[0030] FIG. 6C a flow diagram depicting one embodiment of the steps
taken by a policy engine to make an access control decision based
upon information received about a local machine;
[0031] FIG. 7 is a flow diagram depicting an embodiment of steps
taken in a method for authorizing a level of access of a client to
a virtual private network connection based on a client-side
attribute; and
[0032] FIG. 8 is a block diagram depicting an embodiment of a
system for authorizing a level of access of a client to a virtual
private network connection based on a client-side attribute.
[0033] FIG. 9 is a block diagram depicting an embodiment of a
session failover environment;
[0034] FIG. 10A is a flow diagram depicting steps of an embodiment
of maintaining IIP addresses of a user via session failover;
[0035] FIG. 10B is a diagram depicting example embodiments of user
scenarios of maintaining IIP address information via session
failover; and
[0036] FIG. 11 is a flow diagram depicting steps of an embodiment
for performing end point authorization upon failover.
[0037] The features and advantages of the present invention will
become more apparent from the detailed description set forth below
when taken in conjunction with the drawings, in which like
reference characters identify corresponding elements throughout. In
the drawings, like reference numbers generally indicate identical,
functionally similar, and/or structurally similar elements.
DETAILED DESCRIPTION OF THE INVENTION
[0038] For purposes of reading the description of the various
embodiments of the present invention below, the following
descriptions of the sections of the specification and their
respective contents may be helpful: [0039] Section A describes a
network environment and computing environment useful for practicing
an embodiment of the present invention; [0040] Section B describes
embodiments of a system and appliance architecture for accelerating
delivery of a computing environment to a remote user; [0041]
Section C describes embodiments of a client agent for accelerating
communications between a client and a server; [0042] Section D
describes embodiments of an appliance environment for managing
Intranet Internet Protocol (IIP) addresses; [0043] Section E
describes embodiments of systems and methods for maintaining
Intranet Internet Protocol (IIP) address "stickiness" to a user;
[0044] Section F describes embodiments of systems and methods for
end point detection and authorization using client security
strings; [0045] Section G describes embodiments of an environment
for SSL VPN session failover via appliances; [0046] Section H
describes embodiments of systems and methods for maintaining
Intranet Internet Protocol (IIP) addresses upon SSL VPN session
failover; and [0047] Section I describes embodiments of systems and
methods for end point reauthorization upon SSL VPN session
failover.
A. Network and Computing Environment
[0048] Prior to discussing the specifics of embodiments of the
systems and methods of an appliance and/or client, it may be
helpful to discuss the network and computing environments in which
such embodiments may be deployed. Referring now to FIG. 1A, an
embodiment of a network environment is depicted. In brief overview,
the network environment comprises one or more clients 102a-102n
(also generally referred to as local machine(s) 102, or client(s)
102) in communication with one or more servers 106a-106n (also
generally referred to as server(s) 106, or remote machine(s) 106)
via one or more networks 104, 104' (generally referred to as
network 104). In some embodiments, a client 102 communicates with a
server 106 via an appliance 200.
[0049] Although FIG. 1A shows a network 104 and a network 104'
between the clients 102 and the servers 106, the clients 102 and
the servers 106 may be on the same network 104. The networks 104
and 104' can be the same type of network or different types of
networks. The network 104 and/or the network 104' can be a
local-area network (LAN), such as a company Intranet, a
metropolitan area network (MAN), or a wide area network (WAN), such
as the Internet or the World Wide Web. In one embodiment, network
104' may be a private network and network 104 may be a public
network. In some embodiments, network 104 may be a private network
and network 104' a public network. In another embodiment, networks
104 and 104' may both be private networks. In some embodiments,
clients 102 may be located at a branch office of a corporate
enterprise communicating via a WAN connection over the network 104
to the servers 106 located at a corporate data center.
[0050] The network 104 and/or 104' be any type and/or form of
network and may include any of the following: a point to point
network, a broadcast network, a wide area network, a local area
network, a telecommunications network, a data communication
network, a computer network, an ATM (Asynchronous Transfer Mode)
network, a SONET (Synchronous Optical Network) network, a SDH
(Synchronous Digital Hierarchy) network, a wireless network and a
wireline network. In some embodiments, the network 104 may comprise
a wireless link, such as an infrared channel or satellite band. The
topology of the network 104 and/or 104' may be a bus, star, or ring
network topology. The network 104 and/or 104' and network topology
may be of any such network or network topology as known to those
ordinarily skilled in the art capable of supporting the operations
described herein.
[0051] As shown in FIG. 1A, the appliance 200, which also may be
referred to as an interface unit 200 or gateway 200, is shown
between the networks 104 and 104'. In some embodiments, the
appliance 200 may be located on network 104. For example, a branch
office of a corporate enterprise may deploy an appliance 200 at the
branch office. In other embodiments, the appliance 200 may be
located on network 104'. For example, an appliance 200 may be
located at a corporate data center. In yet another embodiment, a
plurality of appliances 200 may be deployed on network 104. In some
embodiments, a plurality of appliances 200 may be deployed on
network 104'. In one embodiment, a first appliance 200 communicates
with a second appliance 200'. In other embodiments, the appliance
200 could be a part of any client 102 or server 106 on the same or
different network 104,104' as the client 102. One or more
appliances 200 may be located at any point in the network or
network communications path between a client 102 and a server
106.
[0052] In one embodiment, the system may include multiple,
logically-grouped servers 106. In these embodiments, the logical
group of servers may be referred to as a server farm 38. In some of
these embodiments, the serves 106 may be geographically dispersed.
In some cases, a farm 38 may be administered as a single entity. In
other embodiments, the server farm 38 comprises a plurality of
server farms 38. In one embodiment, the server farm executes one or
more applications on behalf of one or more clients 102.
[0053] The servers 106 within each farm 38 can be heterogeneous.
One or more of the servers 106 can operate according to one type of
operating system platform (e.g., WINDOWS NT, manufactured by
Microsoft Corp. of Redmond, Wash.), while one or more of the other
servers 106 can operate on according to another type of operating
system platform (e.g., Unix or Linux). The servers 106 of each farm
38 do not need to be physically proximate to another server 106 in
the same farm 38. Thus, the group of servers 106 logically grouped
as a farm 38 may be interconnected using a wide-area network (WAN)
connection or medium-area network (MAN) connection. For example, a
farm 38 may include servers 106 physically located in different
continents or different regions of a continent, country, state,
city, campus, or room. Data transmission speeds between servers 106
in the farm 38 can be increased if the servers 106 are connected
using a local-area network (LAN) connection or some form of direct
connection.
[0054] Servers 106 may be referred to as a file server, application
server, web server, proxy server, or gateway server. In some
embodiments, a server 106 may have the capacity to function as
either an application server or as a master application server. In
one embodiment, a server 106 may include an Active Directory. The
clients 102 may also be referred to as client nodes or endpoints.
In some embodiments, a client 102 has the capacity to function as
both a client node seeking access to applications on a server and
as an application server providing access to hosted applications
for other clients 102a-102n.
[0055] In some embodiments, a client 102 communicates with a server
106. In one embodiment, the client 102 communicates directly with
one of the servers 106 in a farm 38. In another embodiment, the
client 102 executes a program neighborhood application to
communicate with a server 106 in a farm 38. In still another
embodiment, the server 106 provides the functionality of a master
node. In some embodiments, the client 102 communicates with the
server 106 in the farm 38 through a network 104. Over the network
104, the client 102 can, for example, request execution of various
applications hosted by the servers 106a-106n in the farm 38 and
receive output of the results of the application execution for
display. In some embodiments, only the master node provides the
functionality required to identify and provide address information
associated with a server 106' hosting a requested application.
[0056] In one embodiment, the server 106 provides functionality of
a web server. In another embodiment, the server 106a receives
requests from the client 102, forwards the requests to a second
server 106b and responds to the request by the client 102 with a
response to the request from the server 106b. In still another
embodiment, the server 106 acquires an enumeration of applications
available to the client 102 and address information associated with
a server 106 hosting an application identified by the enumeration
of applications. In yet another embodiment, the server 106 presents
the response to the request to the client 102 using a web
interface. In one embodiment, the client 102 communicates directly
with the server 106 to access the identified application. In
another embodiment, the client 102 receives application output
data, such as display data, generated by an execution of the
identified application on the server 106.
[0057] Referring now to FIG. 1B, a network environment for
delivering and/or operating a computing environment on a client 102
is depicted. In some embodiments, a server 106 includes an
application delivery system 190 for delivering a computing
environment or an application and/or data file to one or more
clients 102. In brief overview, a client 10 is in communication
with a server 106 via network 104, 104' and appliance 200. For
example, the client 102 may reside in a remote office of a company,
e.g., a branch office, and the server 106 may reside at a corporate
data center. The client 102 comprises a client agent 120, and a
computing environment 15. The computing environment 15 may execute
or operate an application that accesses, processes or uses a data
file. The computing environment 15, application and/or data file
may be delivered via the appliance 200 and/or the server 106.
[0058] In some embodiments, the appliance 200 accelerates delivery
of a computing environment 15, or any portion thereof, to a client
102. In one embodiment, the appliance 200 accelerates the delivery
of the computing environment 15 by the application delivery system
190. For example, the embodiments described herein may be used to
accelerate delivery of a streaming application and data file
processable by the application from a central corporate data center
to a remote user location, such as a branch office of the company.
In another embodiment, the appliance 200 accelerates transport
layer traffic between a client 102 and a server 106. The appliance
200 may provide acceleration techniques for accelerating any
transport layer payload from a server 106 to a client 102, such as:
1) transport layer connection pooling, 2) transport layer
connection multiplexing, 3) transport control protocol buffering,
4) compression and 5) caching. In some embodiments, the appliance
200 provides load balancing of servers 106 in responding to
requests from clients 102. In other embodiments, the appliance 200
acts as a proxy or access server to provide access to the one or
more servers 106. In another embodiment, the appliance 200 provides
a secure virtual private network connection from a first network
104 of the client 102 to the second network 104' of the server 106,
such as an SSL VPN connection. It yet other embodiments, the
appliance 200 provides application firewall security, control and
management of the connection and communications between a client
102 and a server 106.
[0059] In some embodiments, the application delivery management
system 190 provides application delivery techniques to deliver a
computing environment to a desktop of a user, remote or otherwise,
based on a plurality of execution methods and based on any
authentication and authorization policies applied via a policy
engine 195. With these techniques, a remote user may obtain a
computing environment and access to server stored applications and
data files from any network connected device 100. In one
embodiment, the application delivery system 190 may reside or
execute on a server 106. In another embodiment, the application
delivery system 190 may reside or execute on a plurality of servers
106a-106n. In some embodiments, the application delivery system 190
may execute in a server farm 38. In one embodiment, the server 106
executing the application delivery system 190 may also store or
provide the application and data file. In another embodiment, a
first set of one or more servers 106 may execute the application
delivery system 190, and a different server 106n may store or
provide the application and data file. In some embodiments, each of
the application delivery system 190, the application, and data file
may reside or be located on different servers. In yet another
embodiment, any portion of the application delivery system 190 may
reside, execute or be stored on or distributed to the appliance
200, or a plurality of appliances.
[0060] The client 102 may include a computing environment 15 for
executing an application that uses or processes a data file. The
client 102 via networks 104, 104' and appliance 200 may request an
application and data file from the server 106. In one embodiment,
the appliance 200 may forward a request from the client 102 to the
server 106. For example, the client 102 may not have the
application and data file stored or accessible locally. In response
to the request, the application delivery system 190 and/or server
106 may deliver the application and data file to the client 102.
For example, in one embodiment, the server 106 may transmit the
application as an application stream to operate in computing
environment 15 on client 102.
[0061] In some embodiments, the application delivery system 190
comprises any portion of the Citrix Access Suite.TM. by Citrix
Systems, Inc., such as the MetaFrame or Citrix Presentation
Server.TM. and/or any of the Microsoft.RTM. Windows Terminal
Services manufactured by the Microsoft Corporation. In one
embodiment, the application delivery system 190 may deliver one or
more applications to clients 102 or users via a remote-display
protocol or otherwise via remote-based or server-based computing.
In another embodiment, the application delivery system 190 may
deliver one or more applications to clients or users via steaming
of the application.
[0062] In one embodiment, the application delivery system 190
includes a policy engine 195 for controlling and managing the
access to, selection of application execution methods and the
delivery of applications. In some embodiments, the policy engine
195 determines the one or more applications a user or client 102
may access. In another embodiment, the policy engine 195 determines
how the application should be delivered to the user or client 102,
e.g., the method of execution. In some embodiments, the application
delivery system 190 provides a plurality of delivery techniques
from which to select a method of application execution, such as a
server-based computing, streaming or delivering the application
locally to the client 120 for local execution.
[0063] In one embodiment, a client 102 requests execution of an
application program and the application delivery system 190
comprising a server 106 selects a method of executing the
application program. In some embodiments, the server 106 receives
credentials from the client 102. In another embodiment, the server
106 receives a request for an enumeration of available applications
from the client 102. In one embodiment, in response to the request
or receipt of credentials, the application delivery system 190
enumerates a plurality of application programs available to the
client 102. The application delivery system 190 receives a request
to execute an enumerated application. The application delivery
system 190 selects one of a predetermined number of methods for
executing the enumerated application, for example, responsive to a
policy of a policy engine. The application delivery system 190 may
select a method of execution of the application enabling the client
102 to receive application-output data generated by execution of
the application program on a server 106. The application delivery
system 190 may select a method of execution of the application
enabling the local machine 10 to execute the application program
locally after retrieving a plurality of application files
comprising the application. In yet another embodiment, the
application delivery system 190 may select a method of execution of
the application to stream the application via the network 104 to
the client 102.
[0064] A client 102 may execute, operate or otherwise provide an
application, which can be any type and/or form of software,
program, or executable instructions such as any type and/or form of
web browser, web-based client, client-server application, a
thin-client computing client, an ActiveX control, or a Java applet,
or any other type and/or form of executable instructions capable of
executing on client 102. In some embodiments, the application may
be a server-based or a remote-based application executed on behalf
of the client 102 on a server 106. In one embodiments the server
106 may display output to the client 102 using any thin-client or
remote-display protocol, such as the Independent Computing
Architecture (ICA) protocol manufactured by Citrix Systems, Inc. of
Ft. Lauderdale, Fla. or the Remote Desktop Protocol (RDP)
manufactured by the Microsoft Corporation of Redmond, Wash. The
application can use any type of protocol and it can be, for
example, an HTTP client, an FTP client, an Oscar client, or a
Telnet client. In other embodiments, the application comprises any
type of software related to VoIP communications, such as a soft IP
telephone. In further embodiments, the application comprises any
application related to real-time data communications, such as
applications for streaming video and/or audio.
[0065] In some embodiments, the server 106 or a server farm 38 may
be running one or more applications, such as an application
providing a thin-client computing or remote display presentation
application. In one embodiment, the server 106 or server farm 38
executes as an application, any portion of the Citrix Access
Suite.TM. by Citrix Systems, Inc., such as the MetaFrame or Citrix
Presentation Server.TM., and/or any of the Microsoft.RTM. Windows
Terminal Services manufactured by the Microsoft Corporation. In one
embodiment, the application is an ICA client, developed by Citrix
Systems, Inc. of Fort Lauderdale, Fla. In other embodiments, the
application includes a Remote Desktop (RDP) client, developed by
Microsoft Corporation of Redmond, Wash. Also, the server 106 may
run an application, which for example, may be an application server
providing email services such as Microsoft Exchange manufactured by
the Microsoft Corporation of Redmond, Wash., a web or Internet
server, or a desktop sharing server, or a collaboration server. In
some embodiments, any of the applications may comprise any type of
hosted service or products, such as GoToMeeting.TM. provided by
Citrix Online Division, Inc. of Santa Barbara, Calif., WebEx.TM.
provided by WebEx, Inc. of Santa Clara, Calif., or Microsoft Office
Live Meeting provided by Microsoft Corporation of Redmond,
Wash.
[0066] The client 102, server 106, and appliance 200 may be
deployed as and/or executed on any type and form of computing
device, such as a computer, network device or appliance capable of
communicating on any type and form of network and performing the
operations described herein. FIGS. 1C and 1D depict block diagrams
of a computing device 100 useful for practicing an embodiment of
the client 102, server 106 or appliance 200. As shown in FIGS. 1C
and 1D, each computing device 100 includes a central processing
unit 101, and a main memory unit 122. As shown in FIG. 1C, a
computing device 100 may include a visual display device 124, a
keyboard 126 and/or a pointing device 127, such as a mouse. Each
computing device 100 may also include additional optional elements,
such as one or more input/output devices 130a-130b (generally
referred to using reference numeral 130), and a cache memory 140 in
communication with the central processing unit 101.
[0067] The central processing unit 101 is any logic circuitry that
responds to and processes instructions fetched from the main memory
unit 122. In many embodiments, the central processing unit is
provided by a microprocessor unit, such as: those manufactured by
Intel Corporation of Mountain View, Calif.; those manufactured by
Motorola Corporation of Schaumburg, Ill.; those manufactured by
Transmeta Corporation of Santa Clara, Calif.; the RS/6000
processor, those manufactured by International Business Machines of
White Plains, N.Y.; or those manufactured by Advanced Micro Devices
of Sunnyvale, Calif. The computing device 100 may be based on any
of these processors, or any other processor capable of operating as
described herein.
[0068] Main memory unit 122 may be one or more memory chips capable
of storing data and allowing any storage location to be directly
accessed by the microprocessor 101, such as Static random access
memory (SRAM), Burst SRAM or SynchBurst SRAM (BSRAM), Dynamic
random access memory (DRAM), Fast Page Mode DRAM (FPM DRAM),
Enhanced DRAM (EDRAM), Extended Data Output RAM (EDO RAM), Extended
Data Output DRAM (EDO DRAM), Burst Extended Data Output DRAM (BEDO
DRAM), Enhanced DRAM (EDRAM), synchronous DRAM (SDRAM), JEDEC SRAM,
PC100 SDRAM, Double Data Rate SDRAM (DDR SDRAM), Enhanced SDRAM
(ESDRAM), SyncLink DRAM (SLDRAM), Direct Rambus DRAM (DRDRAM), or
Ferroelectric RAM (FRAM). The main memory 122 may be based on any
of the above described memory chips, or any other available memory
chips capable of operating as described herein. In the embodiment
shown in FIG. 1C, the processor 101 communicates with main memory
122 via a system bus 150 (described in more detail below). FIG. 1C
depicts an embodiment of a computing device 100 in which the
processor communicates directly with main memory 122 via a memory
port 103. For example, in FIG. 1D the main memory 122 may be
DRDRAM.
[0069] FIG. 1D depicts an embodiment in which the main processor
101 communicates directly with cache memory 140 via a secondary
bus, sometimes referred to as a backside bus. In other embodiments,
the main processor 101 communicates with cache memory 140 using the
system bus 150. Cache memory 140 typically has a faster response
time than main memory 122 and is typically provided by SRAM, BSRAM,
or EDRAM. In the embodiment shown in FIG. 1C, the processor 101
communicates with various I/O devices 130 via a local system bus
150. Various busses may be used to connect the central processing
unit 101 to any of the I/O devices 130, including a VESA VL bus, an
ISA bus, an EISA bus, a MicroChannel Architecture (MCA) bus, a PCI
bus, a PCI-X bus, a PCI-Express bus, or a NuBus. For embodiments in
which the I/O device is a video display 124, the processor 101 may
use an Advanced Graphics Port (AGP) to communicate with the display
124. FIG. 1D depicts an embodiment of a computer 100 in which the
main processor 101 communicates directly with I/O device 130 via
HyperTransport, Rapid I/O, or InfiniBand. FIG. 1D also depicts an
embodiment in which local busses and direct communication are
mixed: the processor 101 communicates with I/O device 130 using a
local interconnect bus while communicating with I/O device 130
directly.
[0070] The computing device 100 may support any suitable
installation device 116, such as a floppy disk drive for receiving
floppy disks such as 3.5-inch, 5.25-inch disks or ZIP disks, a
CD-ROM drive, a CD-R/RW drive, a DVD-ROM drive, tape drives of
various formats, USB device, hard-drive or any other device
suitable for installing software and programs such as any client
agent 120, or portion thereof. The computing device 100 may further
comprise a storage device 128, such as one or more hard disk drives
or redundant arrays of independent disks, for storing an operating
system and other related software, and for storing application
software programs such as any program related to the client agent
120. Optionally, any of the installation devices 116 could also be
used as the storage device 128. Additionally, the operating system
and the software can be run from a bootable medium, for example, a
bootable CD, such as KNOPPIX.RTM., a bootable CD for GNU/Linux that
is available as a GNU/Linux distribution from knoppix.net.
[0071] Furthermore, the computing device 100 may include a network
interface 118 to interface to a Local Area Network (LAN), Wide Area
Network (WAN) or the Internet through a variety of connections
including, but not limited to, standard telephone lines, LAN or WAN
links (e.g., 802.11, T1, T3, 56 kb, X.25), broadband connections
(e.g., ISDN, Frame Relay, ATM), wireless connections, or some
combination of any or all of the above. The network interface 118
may comprise a built-in network adapter, network interface card,
PCMCIA network card, card bus network adapter, wireless network
adapter, USB network adapter, modem or any other device suitable
for interfacing the computing device 100 to any type of network
capable of communication and performing the operations described
herein. A wide variety of I/O devices 130a-130n may be present in
the computing device 100. Input devices include keyboards, mice,
trackpads, trackballs, microphones, and drawing tablets. Output
devices include video displays, speakers, inkjet printers, laser
printers, and dye-sublimation printers. The I/O devices 130 may be
controlled by an I/O controller 123 as shown in FIG. 1C. The I/O
controller may control one or more I/O devices such as a keyboard
126 and a pointing device 127, e.g., a mouse or optical pen.
Furthermore, an I/O device may also provide storage 128 and/or an
installation medium 116 for the computing device 100. In still
other embodiments, the computing device 100 may provide USB
connections to receive handheld USB storage devices such as the USB
Flash Drive line of devices manufactured by Twintech Industry, Inc.
of Los Alamitos, Calif.
[0072] In some embodiments, the computing device 100 may comprise
or be connected to multiple display devices 124a-124n, which each
may be of the same or different type and/or form. As such, any of
the I/O devices 130a-130n and/or the I/O controller 123 may
comprise any type and/or form of suitable hardware, software, or
combination of hardware and software to support, enable or provide
for the connection and use of multiple display devices 124a-124n by
the computing device 100. For example, the computing device 100 may
include any type and/or form of video adapter, video card, driver,
and/or library to interface, communicate, connect or otherwise use
the display devices 124a-124n. In one embodiment, a video adapter
may comprise multiple connectors to interface to multiple display
devices 124a-124n. In other embodiments, the computing device 100
may include multiple video adapters, with each video adapter
connected to one or more of the display devices 124a-124n. In some
embodiments, any portion of the operating system of the computing
device 100 may be configured for using multiple displays 124a-124n.
In other embodiments, one or more of the display devices 124a-124n
may be provided by one or more other computing devices, such as
computing devices 100a and 100b connected to the computing device
100, for example, via a network. These embodiments may include any
type of software designed and constructed to use another computer's
display device as a second display device 124a for the computing
device 100. One ordinarily skilled in the art will recognize and
appreciate the various ways and embodiments that a computing device
100 may be configured to have multiple display devices
124a-124n.
[0073] In further embodiments, an I/O device 130 may be a bridge
170 between the system bus 150 and an external communication bus,
such as a USB bus, an Apple Desktop Bus, an RS-232 serial
connection, a SCSI bus, a FireWire bus, a FireWire 800 bus, an
Ethernet bus, an AppleTalk bus, a Gigabit Ethernet bus, an
Asynchronous Transfer Mode bus, a HIPPI bus, a Super HIPPI bus, a
SerialPlus bus, a SCI/LAMP bus, a FibreChannel bus, or a Serial
Attached small computer system interface bus.
[0074] A computing device 100 of the sort depicted in FIGS. 1C and
1D typically operate under the control of operating systems, which
control scheduling of tasks and access to system resources. The
computing device 100 can be running any operating system such as
any of the versions of the Microsoft.RTM. Windows operating
systems, the different releases of the Unix and Linux operating
systems, any version of the Mac OS.RTM. for Macintosh computers,
any embedded operating system, any real-time operating system, any
open source operating system, any proprietary operating system, any
operating systems for mobile computing devices, or any other
operating system capable of running on the computing device and
performing the operations described herein. Typical operating
systems include: WINDOWS 3.x, WINDOWS 95, WINDOWS 98, WINDOWS 2000,
WINDOWS NT 3.51, WINDOWS NT 4.0, WINDOWS CE, and WINDOWS XP, all of
which are manufactured by Microsoft Corporation of Redmond, Wash.;
MacOS, manufactured by Apple Computer of Cupertino, California;
OS/2, manufactured by International Business Machines of Armonk,
N.Y.; and Linux, a freely-available operating system distributed by
Caldera Corp. of Salt Lake City, Utah, or any type and/or form of a
Unix operating system, among others.
[0075] In other embodiments, the computing device 100 may have
different processors, operating systems, and input devices
consistent with the device. For example, in one embodiment the
computer 100 is a Treo 180, 270, 1060, 600 or 650 smart phone
manufactured by Palm, Inc. In this embodiment, the Treo smart phone
is operated under the control of the PalmOS operating system and
includes a stylus input device as well as a five-way navigator
device. Moreover, the computing device 100 can be any workstation,
desktop computer, laptop or notebook computer, server, handheld
computer, mobile telephone, any other computer, or other form of
computing or telecommunications device that is capable of
communication and that has sufficient processor power and memory
capacity to perform the operations described herein.
B. Appliance Architecture
[0076] FIG. 2A illustrates an example embodiment of the appliance
200. The architecture of the appliance 200 in FIG. 2A is provided
by way of illustration only and is not intended to be limiting. As
shown in FIG. 2, appliance 200 comprises a hardware layer 206 and a
software layer divided into a user space 202 and a kernel space
204.
[0077] Hardware layer 206 provides the hardware elements upon which
programs and services within kernel space 204 and user space 202
are executed. Hardware layer 206 also provides the structures and
elements which allow programs and services within kernel space 204
and user space 202 to communicate data both internally and
externally with respect to appliance 200. As shown in FIG. 2, the
hardware layer 206 includes a processing unit 262 for executing
software programs and services, a memory 264 for storing software
and data, network ports 266 for transmitting and receiving data
over a network, and an encryption processor 260 for performing
functions related to Secure Sockets Layer processing of data
transmitted and received over the network. In some embodiments, the
central processing unit 262 may perform the functions of the
encryption processor 260 in a single processor. Additionally, the
hardware layer 206 may comprise multiple processors for each of the
processing unit 262 and the encryption processor 260. The processor
262 may include any of the processors 101 described above in
connection with FIGS. 1C and 1D. In some embodiments, the central
processing unit 262 may perform the functions of the encryption
processor 260 in a single processor. Additionally, the hardware
layer 206 may comprise multiple processors for each of the
processing unit 262 and the encryption processor 260. For example,
in one embodiment, the appliance 200 comprises a first processor
262 and a second processor 262'. In other embodiments, the
processor 262 or 262' comprises a multi-core processor.
[0078] Although the hardware layer 206 of appliance 200 is
generally illustrated with an encryption processor 260, processor
260 may be a processor for performing functions related to any
encryption protocol, such as the Secure Socket Layer (SSL) or
Transport Layer Security (TLS) protocol. In some embodiments, the
processor 260 may be a general purpose processor (GPP), and in
further embodiments, may be have executable instructions for
performing processing of any security related protocol.
[0079] Although the hardware layer 206 of appliance 200 is
illustrated with certain elements in FIG. 2, the hardware portions
or components of appliance 200 may comprise any type and form of
elements, hardware or software, of a computing device, such as the
computing device 100 illustrated and discussed herein in
conjunction with FIGS. 1C and 1D. In some embodiments, the
appliance 200 may comprise a server, gateway, router, switch,
bridge or other type of computing or network device, and have any
hardware and/or software elements associated therewith.
[0080] The operating system of appliance 200 allocates, manages, or
otherwise segregates the available system memory into kernel space
204 and user space 204. In example software architecture 200, the
operating system may be any type and/or form of Unix operating
system although the invention is not so limited. As such, the
appliance 200 can be running any operating system such as any of
the versions of the Microsoft.RTM. Windows operating systems, the
different releases of the Unix and Linux operating systems, any
version of the Mac OS.RTM. for Macintosh computers, any embedded
operating system, any network operating system, any real-time
operating system, any open source operating system, any proprietary
operating system, any operating systems for mobile computing
devices or network devices, or any other operating system capable
of running on the appliance 200 and performing the operations
described herein.
[0081] The kernel space 204 is reserved for running the kernel 230,
including any device drivers, kernel extensions or other kernel
related software. As known to those skilled in the art, the kernel
230 is the core of the operating system, and provides access,
control, and management of resources and hardware-related elements
of the application 104. In accordance with an embodiment of the
appliance 200, the kernel space 204 also includes a number of
network services or processes working in conjunction with a cache
manager 232. sometimes also referred to as the integrated cache,
the benefits of which are described in detail further herein.
Additionally, the embodiment of the kernel 230 will depend on the
embodiment of the operating system installed, configured, or
otherwise used by the device 200.
[0082] In one embodiment, the device 200 comprises one network
stack 267, such as a TCP/IP based stack, for communicating with the
client 102 and/or the server 106. In one embodiment, the network
stack 267 is used to communicate with a first network, such as
network 108, and a second network 110. In some embodiments, the
device 200 terminates a first transport layer connection, such as a
TCP connection of a client 102, and establishes a second transport
layer connection to a server 106 for use by the client 102, e.g.,
the second transport layer connection is terminated at the
appliance 200 and the server 106. The first and second transport
layer connections may be established via a single network stack
267. In other embodiments, the device 200 may comprise multiple
network stacks, for example 267 and 267', and the first transport
layer connection may be established or terminated at one network
stack 267, and the second transport layer connection on the second
network stack 267'. For example, one network stack may be for
receiving and transmitting network packet on a first network, and
another network stack for receiving and transmitting network
packets on a second network. In one embodiment, the network stack
267 comprises a buffer 243 for queuing one or more network packets
for transmission by the appliance 200.
[0083] As shown in FIG. 2, the kernel space 204 includes the cache
manager 232, a high-speed layer 2-7 integrated packet engine 240,
an encryption engine 234, a policy engine 236 and multi-protocol
compression logic 238. Running these components or processes 232,
240, 234, 236 and 238 in kernel space 204 or kernel mode instead of
the user space 202 improves the performance of each of these
components, alone and in combination. Kernel operation means that
these components or processes 232, 240, 234, 236 and 238 run in the
core address space of the operating system of the device 200. For
example, running the encryption engine 234 in kernel mode improves
encryption performance by moving encryption and decryption
operations to the kernel, thereby reducing the number of
transitions between the memory space or a kernel thread in kernel
mode and the memory space or a thread in user mode. For example,
data obtained in kernel mode may not need to be passed or copied to
a process or thread running in user mode, such as from a kernel
level data structure to a user level data structure. In another
aspect, the number of context switches between kernel mode and user
mode are also reduced. Additionally, synchronization of and
communications between any of the components or processes 232, 240,
235, 236 and 238 can be performed more efficiently in the kernel
space 204.
[0084] In some embodiments, any portion of the components 232, 240,
234, 236 and 238 may run or operate in the kernel space 204, while
other portions of these components 232, 240, 234, 236 and 238 may
run or operate in user space 202. In one embodiment, the appliance
200 uses a kernel-level data structure providing access to any
portion of one or more network packets, for example, a network
packet comprising a request from a client 102 or a response from a
server 106. In some embodiments, the kernel-level data structure
may be obtained by the packet engine 240 via a transport layer
driver interface or filter to the network stack 267. The
kernel-level data structure may comprise any interface and/or data
accessible via the kernel space 204 related to the network stack
267, network traffic or packets received or transmitted by the
network stack 267. In other embodiments, the kernel-level data
structure may be used by any of the components or processes 232,
240, 234, 236 and 238 to perform the desired operation of the
component or process. In one embodiment, a component 232, 240, 234,
236 and 238 is running in kernel mode 204 when using the
kernel-level data structure, while in another embodiment, the
component 232, 240, 234, 236 and 238 is running in user mode when
using the kernel-level data structure. In some embodiments, the
kernel-level data structure may be copied or passed to a second
kernel-level data structure, or any desired user-level data
structure.
[0085] The cache manager 232 may comprise software, hardware or any
combination of software and hardware to provide cache access,
control and management of any type and form of content, such as
objects or dynamically generated objects served by the originating
servers 106. The data, objects or content processed and stored by
the cache manager 232 may comprise data in any format, such as a
markup language, or communicated via any protocol. In some
embodiments, the cache manager 232 duplicates original data stored
elsewhere or data previously computed, generated or transmitted, in
which the original data may require longer access time to fetch,
compute or otherwise obtain relative to reading a cache memory
element. Once the data is stored in the cache memory element,
future use can be made by accessing the cached copy rather than
refetching or recomputing the original data, thereby reducing the
access time. In some embodiments, the cache memory element nat
comprise a data object in memory 264 of device 200. In other
embodiments, the cache memory element may comprise memory having a
faster access time than memory 264. In another embodiment, the
cache memory element may comprise any type and form of storage
element of the device 200, such as a portion of a hard disk. In
some embodiments, the processing unit 262 may provide cache memory
for use by the cache manager 232. In yet further embodiments, the
cache manager 232 may use any portion and combination of memory,
storage, or the processing unit for caching data, objects, and
other content.
[0086] Furthermore, the cache manager 232 includes any logic,
functions, rules, or operations to perform any embodiments of the
techniques of the appliance 200 described herein. For example, the
cache manager 232 includes logic or functionality to invalidate
objects based on the expiration of an invalidation time period or
upon receipt of an invalidation command from a client 102 or server
106. In some embodiments, the cache manager 232 may operate as a
program, service, process or task executing in the kernel space
204, and in other embodiments, in the user space 202. In one
embodiment, a first portion of the cache manager 232 executes in
the user space 202 while a second portion executes in the kernel
space 204. In some embodiments, the cache manager 232 can comprise
any type of general purpose processor (GPP), or any other type of
integrated circuit, such as a Field Programmable Gate Array (FPGA),
Programmable Logic Device (PLD), or Application Specific Integrated
Circuit (ASIC).
[0087] The policy engine 236 may include, for example, an
intelligent statistical engine or other programmable
application(s). In one embodiment, the policy engine 236 provides a
configuration mechanism to allow a user to identifying, specify,
define or configure a caching policy. Policy engine 236, in some
embodiments, also has access to memory to support data structures
such as lookup tables or hash tables to enable user-selected
caching policy decisions. In other embodiments, the policy engine
236 may comprise any logic, rules, functions or operations to
determine and provide access, control and management of objects,
data or content being cached by the appliance 200 in addition to
access, control and management of security, network traffic,
network access, compression or any other function or operation
performed by the appliance 200. Further examples of specific
caching policies are further described herein.
[0088] The encryption engine 234 comprises any logic, business
rules, functions or operations for handling the processing of any
security related protocol, such as SSL or TLS, or any function
related thereto. For example, the encryption engine 234 encrypts
and decrypts network packets, or any portion thereof, communicated
via the appliance 200. The encryption engine 234 may also setup or
establish SSL or TLS connections on behalf of the client 102a-102n,
server 106a-106n, or appliance 200. As such, the encryption engine
234 provides offloading and acceleration of SSL processing. In one
embodiment, the encryption engine 234 uses a tunneling protocol to
provide a virtual private network between a client 102a-102n and a
server 106a-106n. In some embodiments, the encryption engine 234 is
in communication with the Encryption processor 260. In other
embodiments, the encryption engine 234 comprises executable
instructions running on the Encryption processor 260.
[0089] The multi-protocol compression engine 238 comprises any
logic, business rules, function or operations for compressing one
or more protocols of a network packet, such as any of the protocols
used by the network stack 267 of the device 200. In one embodiment,
multi-protocol compression engine 238 compresses bi-directionally
between clients 102a-102n and servers 106a-106n any TCP/IP based
protocol, including Messaging Application Programming Interface
(MAPI) (email), File Transfer Protocol (FTP), HyperText Transfer
Protocol (HTTP), Common Internet File System (CIFS) protocol (file
transfer), Independent Computing Architecture (ICA) protocol,
Remote Desktop Protocol (RDP), Wireless Application Protocol (WAP),
Mobile IP protocol, and Voice Over IP (VoIP) protocol. In other
embodiments, multi-protocol compression engine 238 provides
compression of Hypertext Markup Language (HTML) based protocols and
in some embodiments, provides compression of any markup languages,
such as the Extensible Markup Language (XML). In one embodiment,
the multi-protocol compression engine 238 provides compression of
any high-performance protocol, such as any protocol designed for
appliance 200 to appliance 200 communications. In another
embodiment, the multi-protocol compression engine 238 compresses
any payload of or any communication using a modified transport
control protocol, such as Transaction TCP (T/TCP), TCP with
selection acknowledgements (TCP-SACK), TCP with large windows
(TCP-LW), a congestion prediction protocol such as the TCP-Vegas
protocol, and a TCP spoofing protocol.
[0090] As such, the multi-protocol compression engine 238
accelerates performance for users accessing applications via
desktop clients, e.g., Microsoft Outlook and non-Web thin clients,
such as any client launched by popular enterprise applications like
Oracle, SAP and Siebel, and even mobile clients, such as the Pocket
PC. In some embodiments, the multi-protocol compression engine 238
by executing in the kernel mode 204 and integrating with packet
processing engine 240 accessing the network stack 267 is able to
compress any of the protocols carried by the TCP/IP protocol, such
as any application layer protocol.
[0091] High speed layer 2-7 integrated packet engine 240, also
generally referred to as a packet processing engine or packet
engine, is responsible for managing the kernel-level processing of
packets received and transmitted by appliance 200 via network ports
266. The high speed layer 2-7 integrated packet engine 240 may
comprise a buffer for queuing one or more network packets during
processing, such as for receipt of a network packet or transmission
of a network packer. Additionally, the high speed layer 2-7
integrated packet engine 240 is in communication with one or more
network stacks 267 to send and receive network packets via network
ports 266. The high speed layer 2-7 integrated packet engine 240
works in conjunction with encryption engine 234, cache manager 232,
policy engine 236 and multi-protocol compression logic 238. In
particular, encryption engine 234 is configured to perform SSL
processing of packets, policy engine 236 is configured to perform
functions related to traffic management such as request-level
content switching and request-level cache redirection, and
multi-protocol compression logic 238 is configured to perform
functions related to compression and decompression of data.
[0092] The high speed layer 2-7 integrated packet engine 240
includes a packet processing timer 242. In one embodiment, the
packet processing timer 242 provides one or more time intervals to
trigger the processing of incoming, i.e., received, or outgoing,
i.e., transmitted, network packets. In some embodiments, the high
speed layer 2-7 integrated packet engine 240 processes network
packets responsive to the timer 242. The packet processing timer
242 provides any type and form of signal to the packet engine 240
to notify, trigger, or communicate a time related event, interval
or occurrence. In many embodiments, the packet processing timer 242
operates in the order of milliseconds, such as for example 100 ms,
50 ms or 25 ms. For example, in some embodiments, the packet
processing timer 242 provides time intervals or otherwise causes a
network packet to be processed by the high speed layer 2-7
integrated packet engine 240 at a 10 ms time interval, while in
other embodiments, at a 5 ms time interval, and still yet in
further embodiments, as short as a 3, 2, or 1 ms time interval. The
high speed layer 2-7 integrated packet engine 240 may be
interfaced, integrated or in communication with the encryption
engine 234, cache manager 232, policy engine 236 and multi-protocol
compression engine 238 during operation. As such, any of the logic,
functions, or operations of the encryption engine 234, cache
manager 232, policy engine 236 and multi-protocol compression logic
238 may be performed responsive to the packet processing timer 242
and/or the packet engine 240. Therefore, any of the logic,
functions, or operations of the encryption engine 234, cache
manager 232, policy engine 236 and multi-protocol compression logic
238 may be performed at the granularity of time intervals provided
via the packet processing timer 242, for example, at a time
interval of less than or equal to 10 ms. For example, in one
embodiment, the cache manager 232 may perform invalidation of any
cached objects responsive to the high speed layer 2-7 integrated
packet engine 240 and/or the packet processing timer 242. In
another embodiment, the expiry or invalidation time of a cached
object can be set to the same order of granularity as the time
interval of the packet processing timer 242, such as at every 10
ms.
[0093] In contrast to kernel space 204, user space 202 is the
memory area or portion of the operating system used by user mode
applications or programs otherwise running in user mode. A user
mode application may not access kernel space 204 directly and uses
service calls in order to access kernel services. As shown in FIG.
2, user space 202 of appliance 200 includes a graphical user
interface (GUI) 210, a command line interface (CLI) 212, shell
services 214, health monitoring program 216, and daemon services
218. GUI 210 and CLI 212 provide a means by which a system
administrator or other user can interact with and control the
operation of appliance 200, such as via the operating system of the
appliance 200 and either is user space 202 or kernel space 204. The
GUI 210 may be any type and form of graphical user interface and
may be presented via text, graphical or otherwise, by any type of
program or application, such as a browser. The CLI 212 may be any
type and form of command line or text-based interface, such as a
command line provided by the operating system. For example, the CLI
212 may comprise a shell, which is a tool to enable users to
interact with the operating system. In some embodiments, the CLI
212 may be provided via a bash, csh, tcsh, or ksh type shell. The
shell services 214 comprises the programs, services, tasks,
processes or executable instructions to support interaction with
the appliance 200 or operating system by a user via the GUI 210
and/or CLI 212.
[0094] Health monitoring program 216 is used to monitor, check,
report and ensure that network systems are functioning properly and
that users are receiving requested content over a network. Health
monitoring program 216 comprises one or more programs, services,
tasks, processes or executable instructions to provide logic,
rules, functions or operations for monitoring any activity of the
appliance 200. In some embodiments, the health monitoring program
216 intercepts and inspects any network traffic passed via the
appliance 200. In other embodiments, the health monitoring program
216 interfaces by any suitable means and/or mechanisms with one or
more of the following: the encryption engine 234, cache manager
232, policy engine 236, multi-protocol compression logic 238,
packet engine 240, daemon services 218, and shell services 214. As
such, the health monitoring program 216 may call any application
programming interface (API) to determine a state, status, or health
of any portion of the appliance 200. For example, the health
monitoring program 216 may ping or send a status inquiry on a
periodic basis to check if a program, process, service or task is
active and currently running. In another example, the health
monitoring program 216 may check any status, error or history logs
provided by any program, process, service or task to determine any
condition, status or error with any portion of the appliance
200.
[0095] Daemon services 218 are programs that run continuously or in
the background and handle periodic service requests received by
appliance 200. In some embodiments, a daemon service may forward
the requests to other programs or processes, such as another daemon
service 218 as appropriate. As known to those skilled in the art, a
daemon service 218 may run unattended to perform continuous or
periodic system wide functions, such as network control, or to
perform any desired task. In some embodiments, one or more daemon
services 218 run in the user space 202, while in other embodiments,
one or more daemon services 218 run in the kernel space.
[0096] Referring now to FIG. 2B, another embodiment of the
appliance 200 is depicted. In brief overview, the appliance 200
provides one or more of the following services, functionality or
operations: SSL VPN connectivity 280, switching/load balancing 284,
Domain Name Service resolution 286, acceleration 288 and an
application firewall 290 for communications between one or more
clients 102 and one or more servers 106. In one embodiment, the
appliance 200 comprises any of the network devices manufactured by
Citrix Systems, Inc. of Ft. Lauderdale Fla., referred to as Citrix
NetScaler devices. Each of the servers 106 may provide one or more
network related services 270a-270n (referred to as services 270).
For example, a server 106 may provide an http service 270. The
appliance 200 comprises one or more virtual servers or virtual
internet protocol servers, referred to as a vServer, VIP server, or
just VIP 275a-275n (also referred herein as vServer 275). The
vServer 275 receives, intercepts or otherwise processes
communications between a client 102 and a server 106 in accordance
with the configuration and operations of the appliance 200.
[0097] The vServer 275 may comprise software, hardware or any
combination of software and hardware. The vServer 275 may comprise
any type and form of program, service, task, process or executable
instructions operating in user mode 202, kernel mode 204 or any
combination thereof in the appliance 200. The vServer 275 includes
any logic, functions, rules, or operations to perform any
embodiments of the techniques described herein, such as SSL VPN
280, switching/load balancing 284, Domain Name Service resolution
286, acceleration 288 and an application firewall 290. In some
embodiments, the vServer 275 establishes a connection to a service
270 of a server 106. The service 275 may comprise any program,
application, process, task or set of executable instructions
capable of connecting to and communicating to the appliance 200,
client 102 or vServer 275. For example, the service 275 may
comprise a web server, http server, ftp, email or database server.
In some embodiments, the service 270 is a daemon process or network
driver for listening, receiving and/or sending communications for
an application, such as email, database or an enterprise
application. In some embodiments, the service 270 may communicate
on a specific IP address, or IP address and port.
[0098] In some embodiments, the vServer 275 applies one or more
policies of the policy engine 236 to network communications between
the client 102 and server 106. In one embodiment, the policies are
associated with a VServer 275. In another embodiment, the policies
are based on a user, or a group of users. In yet another
embodiment, a policy is global and applies to one or more vServers
275a-275n, and any user or group of users communicating via the
appliance 200. In some embodiments, the policies of the policy
engine have conditions upon which the policy is applied based on
any content of the communication, such as internet protocol
address, port, protocol type, header or fields in a packet, or the
context of the communication, such as user, group of the user,
vServer 275, transport layer connection, and/or identification or
attributes of the client 102 or server 106.
[0099] In other embodiments, the appliance 200 communicates or
interfaces with the policy engine 236 to determine authentication
and/or authorization of a remote user or a remote client 102 to
access the computing environment 15, application, and/or data file
from a server 106. In another embodiment, the appliance 200
communicates or interfaces with the policy engine 236 to determine
authentication and/or authorization of a remote user or a remote
client 102 to have the application delivery system 190 deliver one
or more of the computing environment 15, application, and/or data
file. In yet another embodiment, the appliance 200 establishes a
VPN or SSL VPN connection based on the policy engine's 236
authentication and/or authorization of a remote user or a remote
client 103 In one embodiment, the appliance 102 controls the flow
of network traffic and communication sessions based on policies of
the policy engine 236. For example, the appliance 200 may control
the access to a computing environment 15, application or data file
based on the policy engine 236.
[0100] In some embodiments, the vServer 275 establishes a transport
layer connection, such as a TCP (Transport Control Protocol) or UDP
(User Datagram Protocol) connection with a client 102 via the
client agent 120. In one embodiment, the vServer 275 listens for
and receives communications from the client 102. In other
embodiments, the vServer 275 establishes a transport layer
connection, such as a TCP or UDP connection with a client server
106. In one embodiment, the vServer 275 establishes the transport
layer connection to an internet protocol address and port of a
server 270 running on the server 106. In another embodiment, the
vServer 275 associates a first transport layer connection to a
client 102 with a second transport layer connection to the server
106. In some embodiments, a vServer 275 establishes a pool of
transport layer connections to a server 106 and multiplexes client
requests via the pooled transport layer connections.
[0101] In some embodiments, the appliance 200 provides a SSL VPN
connection 280 between a client 102 and a server 106. For example,
a client 102 on a first network 102 requests to establish a
connection to a server 106 on a second network 104'. In some
embodiments, the second network 104' is not routable from the first
network 104. In other embodiments, the client 102 is on a public
network 104 and the server 106 is on a private network 104', such
as a corporate network. In one embodiment, the client agent 120
intercepts communications of the client 102 on the first network
104, encrypts the communications, and transmits the communications
via a first transport layer connection to the appliance 200. The
appliance 200 associates the first transport layer connection on
the first network 104 to a second transport layer connection to the
server 106 on the second network 104. The appliance 200 receives
the intercepted communication from the client agent 120, decrypts
the communications, and transmits the communication to the server
106 on the second network 104 via the second transport layer
connection. The second transport layer connection may be a pooled
transport layer connection. As such, the appliance 200 provides an
end-to-end secure transport layer connection for the client 102
between the two networks 104, 104'.
[0102] In one embodiment, the appliance 200 hosts an intranet
internet protocol or intranetIP 282 address of the client 102 on
the virtual private network 104. The client 102 has a local network
identifier, such as an internet protocol (IP) address and/or host
name on the first network 104. When connected to the second network
104' via the appliance 200, the appliance 200 establishes, assigns
or otherwise provides an IntranetIP, which is a network identifier,
such as IP address and/or host name, for the client 102 on the
second network 104'. The appliance 200 listens for and receives on
the second or private network 104' for any communications directed
towards the client 102 using the client's established IntranetIP
282. In one embodiment, the appliance 200 acts as or on behalf of
the client 102 on the second private network 104. For example, in
another embodiment, a vServer 275 listens for and responds to
communications to the IntranetIP 282 of the client 102. In some
embodiments, if a computing device 100 on the second network 104'
transmits a request, the appliance 200 processes the request as if
it were the client 102. For example, the appliance 200 may respond
to a ping to the client's IntranetIP 282. In another example, the
appliance may establish a connection, such as a TCP or UDP
connection, with computing device 100 on the second network 104
requesting a connection with the client's IntranetIP 282.
[0103] In some embodiments, the appliance 200 provides one or more
of the following acceleration techniques 288 to communications
between the client 102 and server 106: 1) compression; 2)
decompression; 3) Transmission Control Protocol pooling; 4)
Transmission Control Protocol multiplexing; 5) Transmission Control
Protocol buffering; and 6) caching. In one embodiment, the
appliance 200 relieves servers 106 of much of the processing load
caused by repeatedly opening and closing transport layers
connections to clients 102 by opening one or more transport layer
connections with each server 106 and maintaining these connections
to allow repeated data accesses by clients via the Internet. This
technique is referred to herein as "connection pooling".
[0104] In some embodiments, in order to seamlessly splice
communications from a client 102 to a server 106 via a pooled
transport layer connection, the appliance 200 translates or
multiplexes communications by modifying sequence number and
acknowledgment numbers at the transport layer protocol level. This
is referred to as "connection multiplexing". In some embodiments,
no application layer protocol interaction is required. For example,
in the case of an in-bound packet (that is, a packet received from
a client 102), the source network address of the packet is changed
to that of an output port of appliance 200, and the destination
network address is changed to that of the intended server. In the
case of an outbound packet (that is, one received from a server
106), the source network address is changed from that of the server
106 to that of an output port of appliance 200 and the destination
address is changed from that of appliance 200 to that of the
requesting client 102. The sequence numbers and acknowledgment
numbers of the packet are also translated to sequence numbers and
acknowledgement expected by the client 102 on the appliance's 200
transport layer connection to the client 102. In some embodiments,
the packet checksum of the transport layer protocol is recalculated
to account for these translations.
[0105] In another embodiment, the appliance 200 provides switching
or load-balancing functionality 284 for communications between the
client 102 and server 106. In some embodiments, the appliance 200
distributes traffic and directs client requests to a server 106
based on layer 4 or application-layer request data. In one
embodiment, although the network layer or layer 2 of the network
packet identifies a destination server 106, the appliance 200
determines the server 106 to distribute the network packet by
application information and data carried as payload of the
transport layer packet. In one embodiment, the health monitoring
programs 216 of the appliance 200 monitor the health of servers to
determine the server 106 for which to distribute a client's
request. In some embodiments, if the appliance 200 detects a server
106 is not available or has a load over a predetermined threshold,
the appliance 200 can direct or distribute client requests to
another server 106.
[0106] In some embodiments, the appliance 200 acts as a Domain Name
Service (DNS) resolver or otherwise provides resolution of a DNS
request from clients 102. In some embodiments, the appliance
intercepts' a DNS request transmitted by the client 102. In one
embodiment, the appliance 200 responds to a client's DNS request
with an IP address of or hosted by the appliance 200. In this
embodiment, the client 102 transmits network communication for the
domain name to the appliance 200. In another embodiment, the
appliance 200 responds to a client's DNS request with an IP address
of or hosted by a second appliance 200'. In some embodiments, the
appliance 200 responds to a client's DNS request with an IP address
of a server 106 determined by the appliance 200.
[0107] In yet another embodiment, the appliance 200 provides
application firewall functionality 290 for communications between
the client 102 and server 106. In one embodiment, the policy engine
236 provides rules for detecting and blocking illegitimate
requests. In some embodiments, the application firewall 290
protects against denial of service (DoS) attacks. In other
embodiments, the appliance inspects the content of intercepted
requests to identify and block application-based attacks. In some
embodiments, the rules/policy engine 236 comprises one or more
application firewall or security control policies for providing
protections against various classes and types of web or Internet
based vulnerabilities, such as one or more of the following: 1)
buffer overflow, 2) CGI-BIN parameter manipulation, 3) form/hidden
field manipulation, 4) forceful browsing, 5) cookie or session
poisoning, 6) broken access control list (ACLs) or weak passwords,
7) cross-site scripting (XSS), 8) command injection, 9) SQL
injection, 10) error triggering sensitive information leak, 11)
insecure use of cryptography, 12) server misconfiguration, 13) back
doors and debug options, 14) website defacement, 15) platform or
operating systems vulnerabilities, and 16) zero-day exploits. In an
embodiment, the application firewall 290 provides HTML form field
protection in the form of inspecting or analyzing the network
communication for one or more of the following: 1) required fields
are returned, 2) no added field allowed, 3) read-only and hidden
field enforcement, 4) drop-down list and radio button field
conformance, and 5) form-field max-length enforcement. In some
embodiments, the application firewall 290 ensures cookies are not
modified. In other embodiments, the application firewall 290
protects against forceful browsing by enforcing legal URLs.
[0108] In still yet other embodiments, the application firewall 290
protects any confidential information contained in the network
communication. The application firewall 290 may inspect or analyze
any network communication in accordance with the rules or polices
of the engine 236 to identify any confidential information in any
field of the network packet. In some embodiments, the application
firewall 290 identifies in the network communication one or more
occurrences of a credit card number, password, social security
number, name, patient code, contact information, and age. The
encoded portion of the network communication may comprise these
occurrences or the confidential information. Based on these
occurrences, in one embodiment, the application firewall 290 may
take a policy action on the network communication, such as prevent
transmission of the network communication. In another embodiment,
the application firewall 290 may rewrite, remove or otherwise mask
such identified occurrence or confidential information.
C. Client Agent
[0109] Referring now to FIG. 3, an embodiment of the client agent
120 is depicted. The client 102 includes a client agent 120 for
establishing and exchanging communications with the appliance 200
and/or server 106 via a network 104. In brief overview, the client
102 operates on computing device 100 having an operating system
with a kernel mode 302 and a user mode 303, and a network stack 310
with one or more layers 310a-310b. The client 102 may have
installed and/or execute one or more applications. In some
embodiments, one or more applications may communicate via the
network stack 310 to a network 104. One of the applications, such
as a web browser, may also include a first program 322. For
example, the first program 322 may be used in some embodiments to
install and/or execute the client agent 120, or any portion
thereof. The client agent 120 includes an interception mechanism,
or interceptor 350, for intercepting network communications from
the network stack 310 from the one or more applications.
[0110] The network stack 310 of the client 102 may comprise any
type and form of software, or hardware, or any combinations
thereof, for providing connectivity to and communications with a
network. In one embodiment, the network stack 310 comprises a
software implementation for a network protocol suite. The network
stack 310 may comprise one or more network layers, such as any
networks layers of the Open Systems Interconnection (OSI)
communications model as those skilled in the art recognize and
appreciate. As such, the network stack 310 may comprise any type
and form of protocols for any of the following layers of the OSI
model: 1) physical link layer, 2) data link layer, 3) network
layer, 4) transport layer, 5) session layer, 6) presentation layer,
and 7) application layer. In one embodiment, the network stack 310
may comprise a transport control protocol (TCP) over the network
layer protocol of the internet protocol (IP), generally referred to
as TCP/IP. In some embodiments, the TCP/IP protocol may be carried
over the Ethernet protocol, which may comprise any of the family of
IEEE wide-area-network (WAN) or local-area-network (LAN) protocols,
such as those protocols covered by the IEEE 802.3. In some
embodiments, the network stack 310 comprises any type and form of a
wireless protocol, such as IEEE 802.11 and/or mobile internet
protocol.
[0111] In view of a TCP/IP based network, any TCP/IP based protocol
may be used, including Messaging Application Programming Interface
(MAPI) (email), File Transfer Protocol (FTP), HyperText Transfer
Protocol (HTTP), Common Internet File System (CIFS) protocol (file
transfer), Independent Computing Architecture (ICA) protocol,
Remote Desktop Protocol (RDP), Wireless Application Protocol (WAP),
Mobile IP protocol, and Voice Over IP (VoIP) protocol. In another
embodiment, the network stack 310 comprises any type and form of
transport control protocol, such as a modified transport control
protocol, for example a Transaction TCP (T/TCP), TCP with selection
acknowledgements (TCP-SACK), TCP with large windows (TCP-LW), a
congestion prediction protocol such as the TCP-Vegas protocol, and
a TCP spoofing protocol. In other embodiments, any type and form of
user datagram protocol (UDP), such as UDP over IP, may be used by
the network stack 310, such as for voice communications or
real-time data communications.
[0112] Furthermore, the network stack 310 may include one or more
network drivers supporting the one or more layers, such as a TCP
driver or a network layer driver. The network drivers may be
included as part of the operating system of the computing device
100 or as part of any network interface cards or other network
access components of the computing device 100. In some embodiments,
any of the network drivers of the network stack 310 may be
customized, modified or adapted to provide a custom or modified
portion of the network stack 310 in support of any of the
techniques described herein. In other embodiments, the acceleration
program 120 is designed and constructed to operate with or work in
conjunction with the network stack 310 installed or otherwise
provided by the operating system of the client 102.
[0113] The network stack 310 comprises any type and form of
interfaces for receiving, obtaining, providing or otherwise
accessing any information and data related to network
communications of the client 102. In one embodiment, an interface
to the network stack 310 comprises an application programming
interface (API). The interface may also comprise any function call,
hooking or filtering mechanism, event or call back mechanism, or
any type of interfacing technique. The network stack 310 via the
interface may receive or provide any type and form of data
structure, such as an object, related to functionality or operation
of the network stack 310. For example, the data structure may
comprise information and data related to a network packet or one or
more network packets. In some embodiments, the data structure
comprises a portion of the network packet processed at a protocol
layer of the network stack 310, such as a network packet of the
transport layer. In some embodiments, the data structure 325
comprises a kernel-level data structure, while in other
embodiments, the data structure 325 comprises a user-mode data
structure. A kernel-level data structure may comprise a data
structure obtained or related to a portion of the network stack 310
operating in kernel-mode 302, or a network driver or other software
running in kernel-mode 302, or any data structure obtained or
received by a service, process, task, thread or other executable
instructions running or operating in kernel-mode of the operating
system.
[0114] Additionally, some portions of the network stack 310 may
execute or operate in kernel-mode 302, for example, the data link
or network layer, while other portions execute or operate in
user-mode 303, such as an application layer of the network stack
310. For example, a first portion 310a of the network stack may
provide user-mode access to the network stack 310 to an application
while a second portion 310a of the network stack 310 provides
access to a network. In some embodiments, a first portion 310a of
the network stack may comprise one or more upper layers of the
network stack 310, such as any of layers 5-7. In other embodiments,
a second portion 310b of the network stack 310 comprises one or
more lower layers, such as any of layers 1-4. Each of the first
portion 310a and second portion 310b of the network stack 310 may
comprise any portion of the network stack 310, at any one or more
network layers, in user-mode 203, kernel-mode, 202, or combinations
thereof, or at any portion of a network layer or interface point to
a network layer or any portion of or interface point to the
user-mode 203 and kernel-mode 203.
[0115] The interceptor 350 may comprise software, hardware, or any
combination of software and hardware. In one embodiment, the
interceptor 350 intercept a network communication at any point in
the network stack 310, and redirects or transmits the network
communication to a destination desired, managed or controlled by
the interceptor 350 or client agent 120. For example, the
interceptor 350 may intercept a network communication of a network
stack 310 of a first network and transmit the network communication
to the appliance 200 for transmission on a second network 104. In
some embodiments, the interceptor 350 comprises any type
interceptor 350 comprises a driver, such as a network driver
constructed and designed to interface and work with the network
stack 310. In some embodiments, the client agent 120 and/or
interceptor 350 operates at one or more layers of the network stack
310, such as at the transport layer. In one embodiment, the
interceptor 350 comprises a filter driver, hooking mechanism, or
any form and type of suitable network driver interface that
interfaces to the transport layer of the network stack, such as via
the transport driver interface (TDI). In some embodiments, the
interceptor 350 interfaces to a first protocol layer, such as the
transport layer and another protocol layer, such as any layer above
the transport protocol layer, for example, an application protocol
layer. In one embodiment, the interceptor 350 may comprise a driver
complying with the Network Driver Interface Specification (NDIS),
or a NDIS driver. In another embodiment, the interceptor 350 may
comprise a mini-filter or a mini-port driver. In one embodiment,
the interceptor 350, or portion thereof, operates in kernel-mode
202. In another embodiment, the interceptor 350, or portion
thereof, operates in user-mode 203. In some embodiments, a portion
of the interceptor 350 operates in kernel-mode 202 while another
portion of the interceptor 350 operates in user-mode 203. In other
embodiments, the client agent 120 operates in user-mode 203 but
interfaces via the interceptor 350 to a kernel-mode driver,
process, service, task or portion of the operating system, such as
to obtain a kernel-level data structure 225. In further
embodiments, the interceptor 350 is a user-mode application or
program, such as application.
[0116] In one embodiment, the interceptor 350 intercepts any
transport layer connection requests. In these embodiments, the
interceptor 350 execute transport layer application programming
interface (API) calls to set the destination information, such as
destination IP address and/or port to a desired location for the
location. In this manner, the interceptor 350 intercepts and
redirects the transport layer connection to a IP address and port
controlled or managed by the interceptor 350 or client agent 120.
In one embodiment, the interceptor 350 sets the destination
information for the connection to a local IP address and port of
the client 102 on which the client agent 120 is listening. For
example, the client agent 120 may comprise a proxy service
listening on a local IP address and port for redirected transport
layer communications. In some embodiments, the client agent 120
then communicates the redirected transport layer communication to
the appliance 200.
[0117] In some embodiments, the interceptor 350 intercepts a Domain
Name Service (DNS) request. In one embodiment, the client agent 120
and/or interceptor 350 resolves the DNS request. In another
embodiment, the interceptor transmits the intercepted DNS request
to the appliance 200 for DNS resolution. In one embodiment, the
appliance 200 resolves the DNS request and communicates the DNS
response to the client agent 120. In some embodiments, the
appliance 200 resolves the DNS request via another appliance 200'
or a DNS server 106.
[0118] In yet another embodiment, the client agent 120 may comprise
two agents 120 and 120'. In one embodiment, a first agent 120 may
comprise an interceptor 350 operating at the network layer of the
network stack 310. In some embodiments, the first agent 120
intercepts network layer requests such as Internet Control Message
Protocol (ICMP) requests (e.g., ping and traceroute). In other
embodiments, the second agent 120' may operate at the transport
layer and intercept transport layer communications. In some
embodiments, the first agent 120 intercepts communications at one
layer of the network stack 210 and interfaces with or communicates
the intercepted communication to the second agent 120'.
[0119] The client agent 120 and/or interceptor 350 may operate at
or interface with a protocol layer in a manner transparent to any
other protocol layer of the network stack 310. For example, in one
embodiment, the interceptor 350 operates or interfaces with the
transport layer of the network stack 310 transparently to any
protocol layer below the transport layer, such as the network
layer, and any protocol layer above the transport layer, such as
the session, presentation or application layer protocols. This
allows the other protocol layers of the network stack 310 to
operate as desired and without modification for using the
interceptor 350. As such, the client agent 120 and/or interceptor
350 can interface with the transport layer to secure, optimize,
accelerate, route or load-balance any communications provided via
any protocol carried by the transport layer, such as any
application layer protocol over TCP/IP.
[0120] Furthermore, the client agent 120 and/or interceptor may
operate at or interface with the network stack 310 in a manner
transparent to any application, a user of the client 102, and any
other computing device, such as a server, in communications with
the client 102. The client agent 120 and/or interceptor 350 may be
installed and/or executed on the client 102 in a manner without
modification of an application. In some embodiments, the user of
the client 102 or a computing device in communications with the
client 102 are not aware of the existence, execution or operation
of the client agent 120 and/or interceptor 350. As such, in some
embodiments, the client agent 120 and/or interceptor 350 is
installed, executed, and/or operated transparently to an
application, user of the client 102, another computing device, such
as a server, or any of the protocol layers above and/or below the
protocol layer interfaced to by the interceptor 350.
[0121] The client agent 120 includes an acceleration program 302, a
streaming client 306, and/or a collection agent 304. In one
embodiment, the client agent 120 comprises an Independent Computing
Architecture (ICA) client, or any portion thereof, developed by
Citrix Systems, Inc. of Fort Lauderdale, Fla., and is also referred
to as an ICA client. In some embodiments, the client 120 comprises
an application streaming client 306 for streaming an application
from a server 106 to a client 102. In some embodiments, the client
agent 120 comprises an acceleration program 302 for accelerating
communications between client 102 and server 106. In another
embodiment, the client agent 120 includes a collection agent 304
for performing end-point detection/scanning and collecting
end-point information for the appliance 200 and/or server 106.
[0122] In some embodiments, the acceleration program 302 comprises
a client-side acceleration program for performing one or more
acceleration techniques to accelerate, enhance or otherwise improve
a client's communications with and/or access to a server 106, such
as accessing an application provided by a server 106. The logic,
functions, and/or operations of the executable instructions of the
acceleration program 302 may perform one or more of the following
acceleration techniques: 1) multi-protocol compression, 2)
transport control protocol pooling, 3) transport control protocol
multiplexing, 4) transport control protocol buffering, and 5)
caching via a cache manager. Additionally, the acceleration program
302 may perform encryption and/or decryption of any communications
received and/or transmitted by the client 102. In some embodiments,
the acceleration program 302 performs one or more of the
acceleration techniques in an integrated manner or fashion.
Additionally, the acceleration program 302 can perform compression
on any of the protocols, or multiple-protocols, carried as a
payload of a network packet of the transport layer protocol.
[0123] The streaming client 306 comprises an application, program,
process, service, task or executable instructions for receiving and
executing a streamed application from a server 106. A server 106
may stream one or more application data files to the streaming
client 306 for playing, executing or otherwise causing to be
executed the application on the client 102. In some embodiments,
the server 106 transmits a set of compressed or packaged
application data files to the streaming client 306. In some
embodiments, the plurality of application files are compressed and
stored on a file server within an archive file such as a CAB, ZIP,
SIT, TAR, JAR or other archive. In one embodiment, the server 106
decompresses, unpackages or unarchives the application files and
transmits the files to the client 102. In another embodiment, the
client 102 decompresses, unpackages or unarchives the application
files. The streaming client 306 dynamically installs the
application, or portion thereof, and executes the application. In
one embodiment, the streaming client 306 may be an executable
program. In some embodiments, the streaming client 306 may be able
to launch another executable program.
[0124] The collection agent 304 comprises an application, program,
process, service, task or executable instructions for identifying,
obtaining and/or collecting information about the client 102. In
some embodiments, the appliance 200 transmits the collection agent
304 to the client 102 or client agent 120. The collection agent 304
may be configured according to one or more policies of the policy
engine 236 of the appliance. In other embodiments, the collection
agent 304 transmits collected information on the client 102 to the
appliance 200. In one embodiment, the policy engine 236 of the
appliance 200 uses the collected information to determine and
provide access, authentication and authorization control of the
client's connection to a network 104.
[0125] In one embodiment, the collection agent 304 comprises an
end-point detection and scanning mechanism, which identifies and
determines one or more attributes or characteristics of the client.
For example, the collection agent 304 may identify and determine
any one or more of the following client-side attributes: 1) the
operating system an/or a version of an operating system, 2) a
service pack of the operating system, 3) a running service, 4) a
running process, and 5) a file. The collection agent 304 may also
identify and determine the presence or versions of any one or more
of the following on the client: 1) antivirus software, 2) personal
firewall software, 3) anti-spam software, and 4) internet security
software. The policy engine 236 may have one or more policies based
on any one or more of the attributes or characteristics of the
client or client-side attributes.
[0126] In some embodiments and still referring to FIG. 3, a first
program 322 may be used to install and/or execute the client agent
120, or portion thereof, such as the interceptor 350,
automatically, silently, transparently, or otherwise. In one
embodiment, the first program 322 comprises a plugin component,
such an ActiveX control or Java control or script that is loaded
into and executed by an application. For example, the first program
comprises an ActiveX control loaded and run by a web browser
application, such as in the memory space or context of the
application. In another embodiment, the first program 322 comprises
a set of executable instructions loaded into and run by the
application, such as a browser. In one embodiment, the first
program 322 comprises a designed and constructed program to install
the client agent 120. In some embodiments, the first program 322
obtains, downloads, or receives the client agent 120 via the
network from another computing device. In another embodiment, the
first program 322 is an installer program or a plug and play
manager for installing programs, such as network drivers, on the
operating system of the client 102.
[0127] Communication between a program neighborhood-enabled client
102 and a server 106 or appliance 200 may occur over a dedicated
virtual channel that is established on top of an ICA virtual
channel. In some embodiments, the communication occurs using an XML
service. In other embodiments, the client 102 runs a client-side
dialog that acquires the credentials of a user of the client 102.
In still other embodiments, a user management subsystem on a server
106 receiving the credentials of the user may return a set of
distinguished names representing the list of accounts to which the
user belongs. Upon authentication, the server 106 may establish a
program neighborhood virtual channel, a control channel, or other
communications channel. In yet other embodiments, an acceleration
program 302 may also be transmitted to the client 102 in response
to a client 102 request.
[0128] In some embodiments, a client 102 may use the client agent
120 to browse farm 38, servers 106 and applications in the farm 38.
In one embodiment, each server 106 includes an ICA browsing
subsystem to provide the client 102 with browsing capability. After
the client 102 establishes a connection with the ICA browser
subsystem of any of the servers 106, that browser subsystem
supports a variety of client 102 requests. Such requests include:
(1) enumerating names of servers in the farm, (2) enumerating names
of applications published in the farm, (3) resolving a server name
and/or application name to a server address that is useful to the
client 102. The ICA browser subsystem also supports requests made
by clients 102 running a program neighborhood application that
provides the client 102, upon request, with a view of those
applications within the farm 38 for which the user is authorized.
The ICA browser subsystem forwards all of the above-mentioned
client requests to the appropriate subsystem in the server 106.
[0129] In one embodiment, a user of the client 102 selects an
application for execution from a received enumeration of available
applications. In another embodiment, the user selects an
application for execution independent of the received enumeration.
In some embodiments, the user selects an application for execution
by selecting a graphical representation of the application
presented on the client 102 by a client agent 120. In other
embodiments, the user selects an application for execution by
selecting a graphical representation of the application presented
to the user on a web server or other server 106. In some
embodiments, an appliance 200 or acceleration program 302
accelerates delivery of the graphical representation. In some
embodiments, an appliance 200 caches or stores the graphical
representation. In some embodiments an appliance 200 may cache or
store any and all of the associated applications or portions of the
associated applications.
[0130] In some embodiments, when a client 102 connects to the
network 104, the user of the client 102 provides user credentials.
User credentials may include the username of a user of the client
102, the password of the user, and the domain name for which the
user is authorized. Alternatively, the user credentials may be
obtained from smart cards, time-based tokens, social security
numbers, user passwords, personal identification (PIN) numbers,
digital certificates based on symmetric key or elliptic curve
cryptography, biometric characteristics of the user, or any other
means by which the identification of the user of the client 102 can
be obtained and submitted for authentication. The server 106 or
appliance 200 responding to the client 102 can authenticate the
user based on the user credentials.
[0131] In some embodiments, the client 102 provides credentials
upon making a request for execution of an application to a server
106, directly or through an appliance 200. In one of these
embodiments, the client 102 requests access to an application
residing on a server 106. In another of these embodiments, the
client 102 requests access to a network on which a desired resource
resides. In other embodiments, the client 102 provides credentials
upon making a request for a connection to an appliance 200. In one
of these embodiments, the client 102 requests access to a virtual
private network. In another of these embodiments, the client 102
requests a network address on the virtual private network. In still
another of these embodiments, the client 102 initiates a connection
to the appliance 200.
[0132] In some embodiments, the user provides credentials to the
server 106 or appliance 200 via a graphical user interface
presented to the client 102 by the server 106 or appliance 200. In
other embodiments, a server 106 or appliance 200 having the
functionality of a web server provides the graphical user interface
to the client 102. In still other embodiments, a collection agent
transmitted to the client 102 by the server 106 or appliance 200
gathers the credentials from the client 102.
[0133] In one embodiment, a credential refers to a username and
password. In another embodiment, a credential is not limited to a
username and password but includes, without limitation, a machine
ID of the client 102, operating system type, existence of a patch
to an operating system, MAC addresses of installed network cards, a
digital watermark on the client device, membership in an Active
Directory, existence of a virus scanner, existence of a personal
firewall, an HTTP header, browser type, device type, network
connection information such as internet protocol address or range
of addresses, machine ID of the server 106 or appliance 200, date
or time of access request including adjustments for varying time
zones, and authorization credentials.
[0134] In some embodiments, a credential associated with a client
102 is associated with a user of the client 102. In one of these
embodiments, the credential is information possessed by the user.
In another of these embodiments, the credential is user
authentication information. In other embodiments, a credential
associated with a client is associated with a network. In one of
these embodiments, the credential is information associated with a
network to which the client may connect. In another of these
embodiments, the credential is information associated with a
network collecting information about the client. In still other
embodiments, a credential associated with a client is a
characteristic of the client.
[0135] In some embodiments, the user authentication performed by
the server 106 or appliance 200 may suffice to authorize the use of
each hosted application program presented to the client 102,
although such applications may reside at another server 106'.
Accordingly, when the client 102 launches (i.e., initiates
execution of) one of the hosted applications, additional input of
user credentials by the client 102 may be unnecessary to
authenticate use of that application. Thus, a single entry of the
user credentials may serve to determine the available applications
and to authorize the launching of such applications without an
additional, manual log-on authentication process by the user.
[0136] In one embodiment, an appliance 200 receives a request for
access to a resource from a client 102. In another embodiment, the
appliance 200 receives a request for access to a virtual private
network. In still another embodiment, the appliance 200 makes a
determination as to whether to grant access and what level of
access to grant. In yet another embodiment, the appliance 200 makes
a determination as to what type of connection to establish when
providing the client with access to the application.
[0137] In some embodiments, decisions regarding whether and how to
grant a user access to a requested resource are made responsive to
determinations by a policy engine regarding whether and how a
client 102 may access an application. In one of these embodiments,
a decision regarding a level of access is made responsive to a
policy engine determination. In another of these embodiments, a
decision regarding a type of access is made responsive to a policy
engine determination. In still another of these embodiments, a
decision regarding a type of connection is made responsive to a
policy engine determination. The policy engine may collect
information about the client 102 prior to making the determination.
In some embodiments, the policy engine resides on the appliance
200. In other embodiments, the appliance 200 is in communication
with a police engine residing on a server 106.
D. IIP Addressing Environment
[0138] Referring now to FIG. 4, an embodiment of an environment for
providing Intranet Internet Protocol (IIP) addresses to users
and/or clients is depicted. The IIP addressing environment provided
by the appliance 200 and/or client 102 may be used for: 1)
assigning, based on policy, temporal and/or status information, an
IIP address 282 to a user from a plurality of IIP addresses
designated to the user for accessing a network via the appliance,
2) providing an IIP address 282 assigned to the user to an
application on a client requesting resolution of the internet
protocol address of the client 102, and 3) providing a mechanism to
determine the IIP address 282 assigned to the user via a
configurable user domain name associated with the user's IIP
address 282.
[0139] In brief overview, the appliance 200 provides an IIP pool
410 of IIP addresses 282A-282N to be assigned and/or used by one or
more users. The IIP pool 410 may include a pool 412 of free or
unassigned IIP addresses, i.e. a free pool 413, a pool 414 of IIP
addresses that may be reclaimed, i.e., a reclaim pool 414, and/or a
pool 416 of IIP addresses that may be assigned via transfer, i.e.,
a transfer pool 416, such as via the transfer of a session 445,
e.g., a SSL VPN session provided by the appliance 200. In some
embodiments, if an IIP address 282 is not available from the IIP
pool 410, then a mapped IP (MIP) 440 may be used to provide a
client or a user an IIP address 282. For mapped IP, the appliance
200 intercepts an incoming client's IP and replaces it with a MIP
address. Any servers sitting behind the appliance 200 see a MIP
instead of a the client's actual IP address in the IP header field
of traffic directed to them.
[0140] A set of one or more IIP addresses 282A-282N may be
designated for or associated with a user. In one embodiment, the
appliance 200 via an IIP policy 420 provides a user with an IIP
address from a plurality of IIP addresses 282A-282N designated for
the user. For example, the IIP policy 420 may indicate to provide
the user with the most recently used IIP address 282 of the user.
The appliance 200 includes a database or table 450 for maintaining
an association of IIP addresses 286 to entities, such as users.
[0141] In additional overview, the appliance 200 provides a
mechanism for querying the IIP address 282 assigned to and/or used
by the user. The appliance 200 may be configured with a user domain
name policy 430 specifying a domain suffix 435 to associate with an
identifier of the user. For example, the domain name policy 430 may
indicate to append the domain suffix "mycompany.com" 435 to a user
identifier, such as the user id of the user when logged into the
appliance 200 or network 104'. As a result, in some embodiments,
the appliance 200 associates the user domain name 437 of <user
id>.<domain suffix>, e.g., "userA.mycompany.com" with the
IIP address assigned to the user. The appliance 200 may store in
the domain name service (DNS) 286, or DNS cache the user domain
name 437 in association with the IIP address 282. The appliance 200
can resolve any DNS queries or ping commands based on the user
domain name 437 by providing the associated IIP address 232.
[0142] In further overview, the client agent 120 provides a
mechanism by which the IIP address 282 is provided to an
application. The client agent 120 includes an interception or
hooking mechanism 350 for intercepting any application programming
interface (API) calls of the application related to determining or
resolving the internet protocol address of the client 102, such as
for example, gethostbyname. Instead of providing the internet
protocol address of the client 102 identified in the network stack
310, e.g., the IP address of the client on network 104, the client
agent 120 provides the IIP address 282 assigned to the user via the
appliance 200, such as the IIP address 282 of the client 102 or
user of the client 102 on the second network 104' connected from
the client 102 on a first network 104 via a SSL VPN connection of
the appliance.
[0143] In more detail, the appliance 200 provides an IIP address
282 to a user or the client of the user. In one embodiment, the IIP
address 282 is the internet protocol address of the user, or the
client used by the user, for communications on the network 104'
accessed via the appliance 200. For example, the user may
communicate on a first network 104 via a network stack 310 of a
client 102 that provides an internet protocol (IP) address for the
first network 104, such as for example, 200.100.10.1. From client
102 on the first network 104, the user may establish a connection,
such as an SSL VPN connection, with a second network 104' via the
appliance 200. The appliance 200 provides an IIP address 282 for
the second network 104' to the client and/or user, such as
192.10.1.1. Although the client 102 has an IP address on the first
network 104 (e.g., 200.100.10.1), the user and/or client has an IIP
address 282 or second network IP address (e.g., 192.10.1.1) for
communications on the second network 104'. In one embodiment, the
IIP address 282 is the internet protocol address assigned to the
client 102 on the VPN, or SSL VPN, connected network 104'. In
another embodiment, the appliance 200 provides or acts as a DNS 286
for clients 102 communicating via the appliance 200. In some
embodiments, the appliance 200 assigns or leases internet protocol
addresses, referred to as IIP addresses 282, to client's requesting
an internet protocol address, such as dynamically via Dynamic Host
Configuration Protocol (DHCP).
[0144] The appliance 200 may provide the IIP address 282 from an
IIP pool 410 of one or more IIP addresses 282A-282N. In some
embodiments, the appliance 200 obtains a pool of internet protocol
addresses on network 104' from a server 106 to use for the IIP pool
410. In one embodiment, the appliance 200 obtains an IIP address
pool 410, or portion thereof, from a DNS server 406, such as one
provided via server 106. In another embodiment, the appliance 200
obtains an IIP address pool 410, or portion thereof, from a Remote
Authentication Dial In User Service, RADIUS, server 408, such as
one provided via server 106. In yet another embodiment, the
appliance 200 acts as a DNS server 286 or provides DNS functionally
286 for network 104'. For example, a vServer 275 may be configured
as a DNS 286. In these embodiments, the appliance 200 obtains or
provides an IIP pool from the appliance provided DNS 286.
[0145] The appliance 200 may designate, assign or allocate IIP
addresses for any of the following entities: 1) user, 2) group, 3)
vServer, and d) global. In some embodiments, the IIP pool 410 may
be designated or used for assigning IIP addresses 286 to users. In
other embodiments, IIP pool 410 may include IIP addresses 286 to be
assigned to or used by services of the appliance 200, such as
vServers 275. In other embodiments, IIP pool 410 may include IIP
addresses 286 to be assigned to or used by global or group entities
of the appliance 200. In one embodiment, the IIP pool 410 may
comprise a single pool of IIP addresses. In another embodiment, the
IIP pool 410 may comprise multiple pools or sub-pools of IIP
addresses. In some embodiments, the IIP pool 410 comprises a free
IIP pool 412. In other embodiments, the IIP pool 410 comprises a
reclaimed IIP pool 414. In yet another embodiment, the IIP pool 410
comprises a transfer IIP pool 416. In some embodiments, the IIP
pool 410 comprises any combination of a free IIP pool 412, a
reclaimed IIP pool 414 and/or a transfer IIP pool 416. In one
embodiment, the free IIP pool 413 comprises IP addresses which are
available for usage. In some embodiments, the reclaimed IIP pool
414 comprises IP addresses which are associated with an entity,
such as a user, group or vServer, but are inactive and available
for usage. In other embodiments, the transfer IIP pool 416
comprises IP addresses that are active but can be made available
through a transfer login or transfer session process.
[0146] In some embodiments, the appliance 200 may list or enumerate
internet protocol addresses used for IIP addresses in the IIP pool
410, or in some embodiments, any of the sub-pools 412, 414, 416, in
an order or priority. In some embodiments, the appliance 200
enumerates or lists the IIP addresses of a pool according to the
following scheme: 1) user, 2) group, 3) vServer, and d) global. In
one embodiment, the appliance 200 provides an IIP address from an
IIP pool 410 for assignment based on the order or priority. For
example, the appliance 200 may try to obtain a free IIP address
from the user associated IP free pool 412 first. If an IIP address
is not available from the user portion of the pool, the appliance
200 may then try to obtain a free IIP address from the group
portion of the pool 412, and so on, via the vServer and global
portions of the pool until an IIP address can be assigned.
Likewise, the appliance 200 may prioritize the sub-pools 412, 414,
and 416, in any order or combination, to search for IIP addresses
to assign. For example, the appliance 200 may first search the free
IIP pool 412, then the reclaimed IIP pool 416 and then the transfer
IIP pool 416 for IIP addresses.
[0147] The appliance 200 may comprise any type and form of database
or table 450 for associating, tracking, managing or maintaining the
designation, allocation and/or assignment of IIP addresses to a 1)
user, 2) group, 3) vServer, and/or d) global entities from the IIP
pool 410. In one embodiment, the appliance 200 implements an
Internet Protocol Light Weight Database Table (IPLWDB) 450. In some
embodiments, the IPLWDB 450 maintains entries which provide a
one-to-one mapping of an IP address with or to an entity. In
another embodiment, once an entity uses or is assigned an IIP
address 282, the IPLWDB maintains the association between the
entity and IIP address, which may be referred to as "IIP
stickiness" or having the IIP address "stuck" to an entity. In one
embodiment, IIP stickiness refers to the ability or effectiveness
of the appliance 200 to maintain or hold the association between
the entity and the IIP address. In some embodiments, IIP stickiness
refers to the ability or effectiveness of the appliance 200 to
maintain the entity/IIP address relationship or assignment via any
changes in the system, such as a user logging in and out of the
appliance, or changing access points. In some embodiments, the
IPLWDB 450 comprises a hash table, which is hashed based on any one
or more of the 1) user, 2) group, 3) vServer, and/or d) global
entities. The IPLWDB 450 may comprise a hash of the user and any
other information associated with the user, such as client 102, or
network 104 of client 104.
[0148] The IPLWDB 450 may track, manage or maintain any status and
temporal information related to the IIP address/entity
relationship. In one embodiment, the IPLWDB 450 maintains if the
IIP address for the entity is currently active or inactive. For
example, in some embodiments, the IPLWDB 450 identifies an IIP
address 282 as active if it is currently used in an SSL VPN session
via the appliance 200. In another embodiment, the IPLWDB 450
maintains temporal data for the IIP address use by the entity: such
as when first used, when last used, how long has been used, and
when most recently used. In other embodiments, the IPLWDB 450
maintains information on the type or source of usage, such as, in
the case of user, what client 102 or network 104 used from, or for
what transactions or activities were performed using the assigned
IIP address.
[0149] In some embodiments, the IPLWDB 450 tracks, manages and
maintains multiple IIP addresses used by an entity. The IPLWDB 450
may use one or more IIP policies 420 for determining which IIP
address of a plurality of IIP addresses to assign or provide to an
entity, such as a user. In one embodiment, the IIP policy 420 may
specify to provide for assignment the most recently or last used
IIP address of the user. In some embodiments, the IIP policy 420
may specify to provide for assignment the most used IIP address of
the user. In other embodiments, the IIP policy 420 may specify to
provide the least used IIP address of the user. In another
embodiment, the IIP policy 420 may specify the order or priority
for which to provide IP addresses of the user, for example, from
the most recent to least recent. In yet another embodiment, the IIP
policy 420 may specify which IIP pool 410 or sub-pool 412, 414, 416
to use, and/or in which order. In some embodiments, the IIP policy
420 may specify whether or not to use a mapped IP address, and
under what conditions, such as when an inactive IIP address of the
user is not available. In other embodiments, the IIP policy 420 may
specify whether or not to transfer a session or login of the user,
and under what conditions.
[0150] In some embodiments, the appliance 200 can be configured to
bind or make the association of one or more IIP addresses 282 to an
entity, such as a user. For example, in some embodiments, the
associations in IPLWDB 450 are updated or maintained via bind and
unbind commands via the appliance 200. In one embodiment, the
following command can be issued to the appliance 200 via a command
line interface (CLI) 212 or GUI 210:
TABLE-US-00001 bind aaa user <user-name> [-intranetip
<ip_addr>] [<netmask>]
For example, if an administrator of the appliance 200 intends to
associate the IIP addresses 282 of 10.102,4,189, 10.102.4.1 and
10.102.4.2 with a user "nsroot", then the administrator may issue
the following commands:
TABLE-US-00002 bind aaa user nsroot -intranetip 10.102.4.189
255.255.255.255 bind aaa user nsroot -intranetip 10.102.4.0 255
255.255.255.252
In one embodiment, the netmask value provides a mechanism for
assigning a range of IIP addresses to a user. In some embodiments,
the netmask value is optional and the default is 255.255.255.255.
For example, the following commands are equivalent:
TABLE-US-00003 bind aaa user nsroot -intranetip 10.102.4.189 bind
aaa user nsroot -intranetip 10.102.4.189 255.255.255.255
Likewise, the administrator 200 or other user may disassociate an
IIP address with an entity, such as a user, via an unbind command.
In some embodiments, the unbind command may have similar format as
the bind command. In one embodiment, if the IIP address is active,
the bind or unbind command will not be processed. In other
embodiments, if the IIP address is active, the appliance transmits
a reset (RST) command to all the client and server connections
associated with the active session, and then proceeds to make any
changes associated with the issued bind or unbind command. In
another embodiment, the appliance 200 updates the associated client
and server connections with any updated IIP address information. In
one embodiment, the appliance 200 re-establishes the associated
client and server connections with the changed IIP address.
[0151] In some embodiments, the appliance 200 provides a mechanism
and/or technique for determining the IIP address 282 of a user. In
one embodiment, the appliance 200 is configured via a user domain
name policy 430, which provides information on specifying a user
domain 437. In one embodiment, the user domain policy 430 specifies
a domain suffix 435 to be used in forming the user domain 437. For
example, the user domain policy 430, in some embodiments, may be
specified by the following command:
TABLE-US-00004 add vpn sessionaction <name> [-httpPort
<port>...] [-winsIP <ip_addr>] ... .... [-homepage
<URL>] [-iipdnssuffix <string>]
In one embodiment, the iipdnssuffix 435 specifies a string, such as
a domain name, that will be appended to the user id/name to form a
user domain name 437. The user id may be the login name of the
user, an alias or nickname of the user, or any user identification
associated with the user's profile. In one embodiment, the domain
suffix 435 identifies the domain name of the network 104 or network
104'. In other embodiments, the domain suffix 435 may comprise a
domain name or host name of the appliance 200. In yet other
embodiments, the domain suffix 435 may be any desired,
predetermined or custom string for identifying the user domain name
437.
[0152] In the case of a user having multiple IIP addresses 282
active concurrently, the user domain name policy 430 may specify an
instance identifier or any other character or symbol to
differentiate between a first instance and a second instance of a
VPN session of the user. For example, the policy 430 may specify to
include a number after the user id, such as
<userid><Instance Number> or <userid>_<#>.
In other embodiments, the policy 430 specifies to only associate or
provide a single user domain name 437 for a user. For example, in
one embodiment, the user domain name 437 is associated with the
first session. In other embodiments, the user domain name 437 is
associated with the most recent session.
[0153] Although the user domain policy 430 is described as
providing a domain suffix 435 to a user identifier to form the user
domain name 437, the user domain policy 430 may specify any portion
of the user domain name 437. For the example, the user domain
policy 430 may specify the format for the user identifier or which
type of user id to use, such as an identified portion of the user's
profile. In some embodiments, by default, the domain suffix 435 may
be the same domain name as the network 104. In another embodiment,
the user domain policy 430 may specify a format for or additions or
modifications to the domain name of the network 104 in providing
the user domain name 437.
[0154] When a user logs in and gets assigned an IIP address 282,
the appliance 200 stores a record associating the user id/name, or
user domain name 437, and IIP address 282. In some embodiments, the
appliance 200 stores the record in DNS 286, or a DNS cache, on the
appliance 200. In another embodiment, the appliance 200 stores the
record in a DNS 406 on server 106. In other embodiments, the
appliance 200 stores the record in the IPLWDB 450. The appliance
200 can query a DNS with the user domain name 437 and obtain the
assigned IIP address 286. A user logged into the appliance 200 via
SSL VPN get the IIP address of another user by using DNS instead of
having to remember the IP address. For example, a user on client
102 can ping the IIP address of another user. The client agent 120
can intercept such requests and query the DNS 286 of the appliance
200 to determine the IIP address 282 assigned the user domain name.
In some embodiments, without logging into the appliance 200 via
SSLVPN, a client can query the IIP address 282 of a user by sending
a DNS query request to the DNS 286 of the appliance 200.
[0155] In some embodiments, the client agent 120 provide an
interception or hooking mechanism 350 for intercepting any requests
for the local IP address of the client 102, and returning or
replying with an IIP address 282, such as the IIP address 282
assigned to the user. In some embodiments, the hooking mechanism
350 may include any of the mechanisms of the interceptor 350
described above in conjunction with FIG. 3. In other embodiments,
the hooking mechanism 350 may include any type and form of hooking
mechanism 350, such as application level hook procedure or
function. In one embodiment and by way of example, the hooking
mechanism 350 comprises any of the Windows API calls for setting a
application hooking procedure, such as via the SetWindowsHookEx API
call. In some embodiments, the SetWindowsHookEx function installs
an application-defined hook procedure into a hook chain.
[0156] Depending on the operating system of the client 102, the
client agent 120 may use the corresponding APIs of the OS to
install, add, modify or use a hook procedure 350 to hook or
intercept messages of an application. A hook procedure 350 may be
installed to monitor the system for certain types of events, which
are associated either with a specific thread or with all threads in
the same space as the calling thread. In one embodiment, a hook,
such as hooking mechanism 350, is a point in the system
message-handling mechanism where an application, such as the client
agent 120, can install a subroutine to monitor the message traffic
in the system and process certain types of messages before the
messages reach the target processing function. In some embodiments,
the hooking mechanism 350 may intercept or hook any of the
following function calls or messages of an application:
gethostbyname, getaddrinfo, and getsockname. In other embodiments,
the hooking mechanism 350 may hook any of the Windows Socket API
extensions such as WSAIoctl, WSALookupServiceBegin,
WSALookupServiceNext, and WSALookupServiceEnd.
[0157] In one embodiment, the client agent 120 transmits a request
to the appliance 200 to determine the IIP address 282 of the host
name intercepted by the hooking mechanism 350. In some embodiments,
the appliance 200 looks up the corresponding IIP address 282 of the
host name of the client 102 in a DNS, such as DNS 286 on appliance
200 or DNS 406 on a server. In other embodiments, the client agent
120 uses the user domain name 437 of the user associated with the
application to ping or DNS query the IIP address 282. In some
embodiments, the client agent 120 transmits the local IP address of
the client 102 and the appliance 200 queries the corresponding IIP
address 282. In one embodiment, the appliance 200 stores the name
of the client 102 in association with the user and/or IIP address
in the IPLWDB 450. In other embodiments, the client agent 120 has
cached the IIP address of the user or client 102, and thus, does
not need to query the appliance 200. For example, upon
establishment of a SSL VPN connection, the appliance 200 may
transmit the IIP address 282 to the client 102. With the hooking
mechanism 350, instead of providing the client's local IP address
(the client's address on the first network 104), the client agent
120 provides the IIP address 282 of the client (the client's or
user's address on the second network 104').
[0158] In some embodiments, the hooking mechanism 350 of the client
agent 120 is used to return the IIP address for supporting the
transparent and seamless use of online collaboration tools via SSL
VPN connections. In one embodiment, the application is a NetMeeting
application manufactured by the Microsoft Corporation of Redmond,
Wash. In some embodiments, any of the applications 230 may comprise
any type of hosted service or products, such as GoToMeeting.TM.
provided by Citrix Online Division, Inc. of Santa Barbara, Calif.,
WebEX.TM. provided by WebEx, Inc. of Santa Clara, Calif., or
Microsoft Office LiveMeeting provided by Microsoft Corporation of
Redmond, Wash. With the hooking mechanism 350 providing the IIP
address 282 assigned to the client via the SSL VPN connection, the
application does not need to be modified to work as designed via
the SSL VPN session. The hooking mechanism 350 provides the IIP
address 282 of the client 102 or user if the client 102 instead of
the local IP address when making a request to get the IP address of
the client 102.
[0159] Communication between a program neighborhood-enabled client
102 and a server 106 or appliance 200 may occur over a dedicated
virtual channel that is established on top of an ICA virtual
channel. In some embodiments, the communication occurs using an XML
service. In other embodiments, the client 102 runs a client-side
dialog that acquires the credentials of a user of the client 102.
In still other embodiments, a user management subsystem on a server
106 receiving the credentials of the user may return a set of
distinguished names representing the list of accounts to which the
user belongs. Upon authentication, the server 106 may establish a
program neighborhood virtual channel, a control channel, or other
communications channel. In yet other embodiments, an acceleration
program 302 may also be transmitted to the client 102 in response
to a client 102 request.
[0160] In some embodiments, a client 102 may use the client agent
120 to browse farm 38, servers 106 and applications in the farm 38.
In one embodiment, each server 106 includes an ICA browsing
subsystem to provide the client 102 with browsing capability. After
the client 102 establishes a connection with the ICA browser
subsystem of any of the servers 106, that browser subsystem
supports a variety of client 102 requests. Such requests include:
(1) enumerating names of servers in the farm, (2) enumerating names
of applications published in the farm, (3) resolving a server name
and/or application name to a server address that is useful to the
client 102. The ICA browser subsystem also supports requests made
by clients 102 running a program neighborhood application that
provides the client 102, upon request, with a view of those
applications within the farm 38 for which the user is authorized.
The ICA browser subsystem forwards all of the above-mentioned
client requests to the appropriate subsystem in the server 106.
[0161] In one embodiment, a user of the client 102 selects an
application for execution from a received enumeration of available
applications. In another embodiment, the user selects an
application for execution independent of the received enumeration.
In some embodiments, the user selects an application for execution
by selecting a graphical representation of the application
presented on the client 102 by a client agent 120. In other
embodiments, the user selects an application for execution by
selecting a graphical representation of the application presented
to the user on a web server or other server 106. In some
embodiments, an appliance 200 or acceleration program 302
accelerates delivery of the graphical representation. In some
embodiments, an appliance 200 caches or stores the graphical
representation. In some embodiments an appliance 200 may cache or
store any and all of the associated applications or portions of the
associated applications.
[0162] In some embodiments, when a client 102 connects to the
network 104, the user of the client 102 provides user credentials.
User credentials may include the username of a user of the client
102, the password of the user, and the domain name for which the
user is authorized. Alternatively, the user credentials may be
obtained from smart cards, time-based tokens, social security
numbers, user passwords, personal identification (PIN) numbers,
digital certificates based on symmetric key or elliptic curve
cryptography, biometric characteristics of the user, or any other
means by which the identification of the user of the client 102 can
be obtained and submitted for authentication. The server 106 or
appliance 200 responding to the client 102 can authenticate the
user based on the user credentials.
[0163] In some embodiments, the client 102 provides credentials
upon making a request for execution of an application to a server
106, directly or through an appliance 200. In one of these
embodiments, the client 102 requests access to an application
residing on a server 106. In another of these embodiments, the
client 102 requests access to a network on which a desired resource
resides. In other embodiments, the client 102 provides credentials
upon making a request for a connection to an appliance 200. In one
of these embodiments, the client 102 requests access to a virtual
private network. In another of these embodiments, the client 102
requests a network address on the virtual private network. In still
another of these embodiments, the client 102 initiates a connection
to the appliance 200.
[0164] In some embodiments, the user provides credentials to the
server 106 or appliance 200 via a graphical user interface
presented to the client 102 by the server 106 or appliance 200. In
other embodiments, a server 106 or appliance 200 having the
functionality of a web server provides the graphical user interface
to the client 102. In still other embodiments, a collection agent
transmitted to the client 102 by the server 106 or appliance 200
gathers the credentials from the client 102.
[0165] In one embodiment, a credential refers to a username and
password. In another embodiment, a credential is not limited to a
username and password but includes, without limitation, a machine
ID of the client 102, operating system type, existence of a patch
to an operating system, MAC addresses of installed network cards, a
digital watermark on the client device, membership in an Active
Directory, existence of a virus scanner, existence of a personal
firewall, an HTTP header, browser type, device type, network
connection information such as internet protocol address or range
of addresses, machine ID of the server 106 or appliance 200, date
or time of access request including adjustments for varying time
zones, and authorization credentials.
[0166] In some embodiments, a credential associated with a client
102 is associated with a user of the client 102. In one of these
embodiments, the credential is information possessed by the user.
In another of these embodiments, the credential is user
authentication information. In other embodiments, a credential
associated with a client is associated with a network. In one of
these embodiments, the credential is information associated with a
network to which the client may connect. In another of these
embodiments, the credential is information associated with a
network collecting information about the client. In still other
embodiments, a credential associated with a client is a
characteristic of the client.
[0167] In some embodiments, the user authentication performed by
the server 106 or appliance 200 may suffice to authorize the use of
each hosted application program presented to the client 102,
although such applications may reside at another server 106'.
Accordingly, when the client 102 launches (i.e., initiates
execution of) one of the hosted applications, additional input of
user credentials by the client 102 may be unnecessary to
authenticate use of that application. Thus, a single entry of the
user credentials may serve to determine the available applications
and to authorize the launching of such applications without an
additional, manual log-on authentication process by the user.
[0168] In one embodiment, an appliance 200 receives a request for
access to a resource from a client 102. In another embodiment, the
appliance 200 receives a request for access to a virtual private
network. In still another embodiment, the appliance 200 makes a
determination as to whether to grant access and what level of
access to grant. In yet another embodiment, the appliance 200 makes
a determination as to what type of connection to establish when
providing the client with access to the application.
[0169] In some embodiments, decisions regarding whether and how to
grant a user access to a requested resource are made responsive to
determinations by a policy engine regarding whether and how a
client 102 may access an application. In one of these embodiments,
a decision regarding a level of access is made responsive to a
policy engine determination. In another of these embodiments, a
decision regarding a type of access is made responsive to a policy
engine determination. In still another of these embodiments, a
decision regarding a type of connection is made responsive to a
policy engine determination. The policy engine may collect
information about the client 102 prior to making the determination.
In some embodiments, the policy engine resides on the appliance
200. In other embodiments, the appliance 200 is in communication
with a police engine residing on a server 106.
E. IIP Address "Stickiness" to a User
[0170] Referring now to FIG. 5, an embodiment of steps of a method
500 for assigning an IIP address 282 to a user is depicted. In one
embodiment, the method 500 is practiced to provide IIP address
stickiness for a user. In some embodiments, an SSL VPN user may
login and logout of the appliance 200 multiple times from different
computers. For example, the user may roam from computing device to
computing device or switch from one location to another. In some
example, an SSL VPN user may be on a mobile device and have the
network connectivity disrupted causing the device to re-establish
the SSL VPN connection. With the techniques depicted by method 500,
the SSL VPN user may get assigned the same IIP address 282 for each
of those sessions. In some embodiments, the appliance 200 may be
configured with policies 420 specifying what IIP address 282 should
be assigned to a user.
[0171] In brief overview of method 500, at step 505, the appliance
200 designates a plurality of IIP address 282A-292N to a user, such
as an SSL VPN user, from a pool 410 of IIP addresses. At step 510,
the appliance 200 receives a request from a client 102 operated by
the user to establish a connection via the appliance 200 to a
network 104', such as an SSL VPN connection. At step 515, the
appliance 200 assigns to the client or the user an IIP address 282
on network 104' from the IIP address pool 410. The appliance 200
may make the assignment based on policy 420, temporal information
or the status of any of the designated IIP addresses 282A-282N for
the user. For example, in one embodiment, the appliance 200 assigns
the most recently used IIP address 282 of the user to the client
102. At step 525, in some embodiments, the appliance 200 determines
whether to provide a mapped IP or to transfer a session. For
example, if an inactive IIP address 282 is not available for
assigning to the user, the appliance 200 may opt to use a MIP
address at step 530 or to request the user to transfer an active
session to the current request at step 535.
[0172] In further detail, at step 505, the appliance 200 may
designate or allocate any set of one or more IIP addresses
282A-282N for a user. In some embodiments, the appliance 200
designates one IIP address 282. In other embodiments, the appliance
200 designates up to a predetermined number of multiple IIP
addresses 282A-282N for the user, such as 2, 3, 4, 5, 6, 7, 9, 10,
15, 20 or 26 IIP addresses. In one embodiment, the multiple IIP
addresses 282A-228N comprise a continuous range of IP addresses on
network 104', for example, IP addresses 200.10.1.1 to 200.20.1.10.
In another embodiment, the multiple IIP addresses 282A-282N
comprises any set of IP addresses on network 104' that are not
subsequent to each other. In yet another embodiment, the multiple
IIP addresses 282A-282N are any combination of subsequent IP
address ranges and single or separate IP addresses.
[0173] In one embodiment, the appliance 200 obtains a set of
internet protocol addresses from a DNS for the network 104'
accessed via the appliance 200. For example, the appliance 200 may
obtain a set of IP addresses for the intranet from a DNS server 406
or a RADIUS server 508. In another example, the appliance 200 may
provide or act as a DNS 286 and allocate the IP addresses for the
intranet. In some embodiments, one or more IIP addresses 282A-282N
may be associated or designated with a user via a bind or similar
command issued at the CLI 212 or GUI 210 of the appliance 200. In
other embodiments, the appliance 200 may obtain from a DNS IP
addresses 282A-282N on network 104's that are associated with a
user. In some embodiments, the appliance 200 designates a portion
of the free IIP pool 412 to the user. In other embodiments, the
appliance 200 may designate or reclaim a portion of the reclaim IIP
pool 414 to the user.
[0174] At step 510, the user via client 102 transmits a request to
the appliance 200 to establish a connection to the network 104'. In
some embodiments, the appliance 200 identifies the user from the
request. In other embodiments, the appliance 200 identifies the
user from receipt of login or authentication credentials. For
example, in some embodiments, the user submits a user id and
password via a URL or web-page of the appliance 200. In one
embodiment, the client agent 120 requests to establish a tunnel
connection with the appliance 200 using any type and form of
tunneling protocol. In another embodiment, the client agent 120
requests to establish a virtual private network connection via the
appliance 200 to a network 104. For example, the client agent 120
may establish a virtual private network connection with the
appliance 200 to connect the client 102 on the first network 104 to
a second network 104'. In some embodiments, the client agent 120
establishes a SSL VPN connection with the appliance 200. In yet
another embodiment, the client agent 120 establishes a tunnel or
virtual private network connection using Transport Layer Secure
(TLS) protocol. In one embodiment, the client agent 120 requests to
establish a tunnel connection using the Common Gateway Protocol
(CGP) manufactured by Citrix Systems, Inc. of Ft. Lauderdale,
Fla.
[0175] At step 515, the appliance 200, in response to receiving the
request from the user or the client 102, assigns an IIP address 282
on the second network 104' from the designated set of IIP addresses
282A-282N of the user. In one embodiment, the appliance 200
determines the IIP address 282 to assign based on an IIP policy
420. For example, in some embodiments to maintain IIP stickiness,
the appliance 200 via IIP policy 420 determines the most recently
used IIP address 282 of the user. In other embodiments to maintain
IIP stickiness, the appliance 200 via information tracked by the
IPLWDB 450 determines the most used IIP address 282 of the user
from the set of IIP addresses 282A-282N. In some embodiments, in
the case of one or more active SSL VPN sessions, the appliance 200
determines the next most recently used or most used IIP address 282
of the user. In yet other embodiments, the appliance 200 determines
an appropriate, desired or policy-driven IIP address 282 to assign
the user from the designated set of user IIP addresses 282A-282N by
any combination of policy 435, status of sessions associated with
the user's IIP addresses 282A-282N, and temporal information of
sessions associated with the user's IIP addresses 282A-282N.
[0176] In one embodiment, the appliance 200 may use any sub-pool
412, 414 or 416 of the IP pool 410 to assign an IIP address 282 to
the user. In some embodiment, the free IIP pool 412 may not have an
available IIP address of the user. For example, all the IIP
addresses of the user are marked as active or already assigned to a
session. As such, in these embodiments, the appliance 200 may
search the reclaim IIP pool 414 for any IIP addresses of the user
assigned but available to reclaim. In still another embodiment, the
appliance 200 may search the transfer IIP pool 416 for any IIP
addresses of the user. In yet other embodiments, the appliance 200
may search any designated allocations or pools for group, global or
vServer IIP addresses for an IP address that may be designated and
assigned for the user or otherwise provided as a mapped IP address.
In some embodiments, the appliance 200 searches portions of the IP
pool 410 for IIP addresses of the user in an ordered or prioritized
manner, such as the free IIP pool 412, first, the reclaim IIP pool
414, second and the transfer IIP pool 416 third. In one embodiment,
the search order or priority may be specified by a policy 420.
[0177] In many embodiments, the appliance 200 provides a previously
assigned IIP address 282 of the user from the free IIP pool 412 or
the reclaim IIP pool 414. In some embodiments, the appliance 200
provides the user with the most recently or last assigned IIP
address to provide IIP stickiness. However, at step 525, in some
embodiments, the appliance 200 determines whether to provide a
mapped IP 440 or a transfer session 445. In some embodiments, an
IIP policy 420 specifies whether to use a mapped IP 440 or a
transfer session 445 in cases of the appliance 200 not finding an
available IIP address 282 of the user from the free IIP pool 412
and/or the reclaimed IIP pool 414. In other embodiments, an IIP
policy 420 may specify to use a Mapped IP 440 in cases of the
appliance 200 not finding an inactive IIP address in any pool 410,
or an available IIP address in the free IIP pool 412. In one
embodiment, if the IIP policy 420 specifies to use a Mapped IP 440
at step 525, then, at step 530 provides a Mapped IP 440 instead of
using an assigned IIP address 272.
[0178] In the cases of using a Mapped IP 440, the appliance 200
modifies any packets to and from the client 102 with an IIP address
282 of the network 104'. For example, instead of assigning the user
a user designated IIP address 282, the appliance 200 may use any
available IIP address of the IIP pool 410, such as a globally
available IIP address. The appliance 200 may modify the packets
transmitted from the client 102 to have this mapped IP 440 when
transmitted from the appliance 200 to a server 106. Also, in some
embodiments, the appliance 200 may modify packets transmitted from
the server 106 to the client 102 to change the Mapped IP 440 to the
IP address of the client 102, such as the IP address of the client
102 on the first network 104. In some embodiments, the appliance
200 stores in the IPLWDB 450 the association of the mapped IP 440
to the user and/or client 102.
[0179] In another embodiment, if the IIP policy 420 specifies to
use a transfer session 445 at step 525, then, at step 535, the
appliance 200 initiates a transfer of an active session of the
user. In one embodiment, upon receiving, by the appliance 200, a
request from a first client operated by a user to establish a VPN
session, the appliance may create a temporary VPN session with the
client. In some embodiments, the appliance 200 may refuse to accept
any data received via the temporary session until a new VPN session
is created from temporary session. In other embodiments, the
temporary VPN session may be allocated less resources by the
appliance than would be allocated to a standard VPN session. In
another embodiment, a temporary VPN session may not be assigned an
IIP address 282, or may otherwise be prevented from receiving data.
In some embodiments, the appliance may identify a number of
properties associated with the existing session. In one embodiment,
after identifying an existing session, the appliance 200 may
transmit a message to the user via the previously existing session
indicating the current session attempt.
[0180] In some embodiments, the appliance 200 may transmit to the
client 102 of the user a request for information corresponding to
whether to terminate the previous session. In some embodiments,
this request may comprise a web page which accepts user input. For
example, the web page may comprise an enumerated list of existing
sessions, with input means for the user to a select one or more
sessions to be terminated. In other embodiments, this request may
comprise a communication to a client agent 120, which then may
respond on behalf of the user. In some embodiments, this request
may comprise a request for information corresponding to whether to
terminate one or more of a plurality of previous sessions.
[0181] In one embodiment, the request may comprise information
relating to any of the properties of the existing session. In some
embodiments, this information may be displayed to the user along
with the choice of whether to terminate the existing session. For
example, a web page may be displayed to the user stating "you have
a previously existing session which was opened July 2nd at 10:30
am, do you wish to close?" In other embodiments, this information
may be transmitted to a client agent which may then make a
determination whether to close a previously existing session based
on the properties of the previously existing session. For example,
a client agent 120 executing on the client making the new session
request may determine to automatically terminate a previous session
in the event that no applications are currently associated with the
previous session.
[0182] In some embodiments, the request may also comprise a request
for information relating to whether the user would like to transfer
data from a previous session to a current session. For example, if
a user was remotely executing an application, the user may wish to
resume the remote execution and the previous session or sessions
associated with the remote execution using the current session.
After transmitting, from the appliance 200 to the client 102, a
request for information corresponding to whether to terminate the
previous session the appliance may receive, from the client or the
user, a response comprising an indication to terminate the previous
session. In still other embodiments, the appliance 200 may receive
a response comprising a request to transfer data associated with a
previous session to the current session. In these embodiments, the
appliance 200 assigns the IIP address 282A of the previous session
to the new session.
[0183] In the event the appliance 200 receives a response
comprising an indication not to terminate the previous session, the
appliance 200 may refuse to allow the user access, and terminate
the temporary VPN session. In these embodiments, the appliance 200
maintains the association of the IIP addresses 282 with the
previous session and does not assign the IIP address to the new
session. In other embodiments, the appliance 200 may create a new
VPN session unrelated to any of the identified previous sessions.
In these embodiments, the appliance 200 may assign an available IIP
address from another entity, such as group, vServer or global or
another user, to the new VPN session.
F. Client End-Point Detection and Authorization Via Client Security
String
[0184] Referring now to FIG. 6A, one embodiment of a computer
network is depicted, which includes a client 102, a collection
agent 304, a policy engine 235, a policy database 608, a server
farm 38, and an application server 106. In one embodiment, the
policy engine 236 is a server 106. Although only one client 102,
collection agent 304, policy engine 236, server farm 38, and
application server 106 are depicted in the embodiment shown in FIG.
6A, it should be understood that the system may provide multiple
ones of any or each of those components.
[0185] In brief overview, when the client 102 transmits a request
610 to the policy engine 236 for access to an application, the
collection agent 304 communicates with client 102, retrieving
information about the client 102, and transmits the client
information 612 to the policy engine 236. The policy engine 236
makes an access control decision by applying a policy from the
policy database 608 to the received information 612.
[0186] In more detail, the client 102 transmits a request 610 for a
resource to the policy engine 236. In one embodiment, the policy
engine 236 resides on an application server 106'. In another
embodiment, the policy engine 236 is a server 106. In still another
embodiment, the policy engine 236 resides on an appliance 200. In
yet another embodiment, an application server 106' or an appliance
200 receives the request 610 from the client 102 and transmits the
request 610 to the policy engine 236. In a further embodiment, the
client 102 transmits a request 610 for a resource to a server 106,
which transmits the request 610 to the policy engine 236.
[0187] Upon receiving the request, the policy engine 236 initiates
information gathering by the collection agent 304. The collection
agent 304 gathers information regarding the client 102 and
transmits the information 612 to the policy engine 236.
[0188] In some embodiments, the collection agent 304 gathers and
transmits the information 612 over a network connection. In some
embodiments, the collection agent 304 comprises bytecode, such as
an application written in the bytecode programming language JAVA.
In some embodiments, the collection agent 304 comprises at least
one script. In those embodiments, the collection agent 304 gathers
information by running at least one script on the client 102. In
some embodiments, the collection agent comprises an Active X
control on the client 102. An Active X control is a specialized
Component Object Model (COM) object that implements a set of
interfaces that enable it to look and act like a control.
[0189] In one embodiment, the policy engine 236 transmits the
collection agent 304 to the client 102. In another embodiment, an
appliance 200 may store or cache the collection agent 304. The
appliance 200 may then transmit the collection agent to a client
102. In other embodiments, an appliance 200 may intercept the
transmission of a collection agent 304. In still another
embodiment, an appliance 200 may accelerate the delivery of a
collection agent 304. In one embodiment, the policy engine 236
requires a second execution of the collection agent 304 after the
collection agent 304 has transmitted information 612 to the policy
engine 236. In this embodiment, the policy engine 236 may have
insufficient information 612 to determine whether the client 102
satisfies a particular condition. In other embodiments, the policy
engine 236 requires a plurality of executions of the collection
agent 304 in response to received information 612.
[0190] In some embodiments, the policy engine 236 transmits
instructions to the collection agent 304 determining the type of
information the collection agent 304 gathers. In those embodiments,
a system administrator may configure the instructions transmitted
to the collection agent 304 from the policy engine 236. This
provides greater control over the type of information collected.
This also expands the types of access control decisions that the
policy engine 236 can make, due to the greater control over the
type of information collected. The collection agent 304 gathers
information 612 including, without limitation, machine ID of the
client 102, operating system type, existence of a patch to an
operating system, MAC addresses of installed network cards, a
digital watermark on the client device, membership in an Active
Directory, existence of a virus scanner, existence of a personal
firewall, an HTTP header, browser type, device type, network
connection information such as internet protocol address or range
of addresses, machine ID of the server 106, date or time of access
request including adjustments for varying time zones, and
authorization credentials. In some embodiments, a collection agent
gathers information to determine whether an application can be
accelerated on the client using an acceleration program 302.
[0191] In some embodiments, the device type is a personal digital
assistant. In other embodiments, the device type is a cellular
telephone. In other embodiments, the device type is a laptop
computer. In other embodiments, the device type is a desktop
computer. In other embodiments, the device type is an Internet
kiosk.
[0192] In some embodiments, the digital watermark includes data
embedding. In some embodiments, the watermark comprises a pattern
of data inserted into a file to provide source information about
the file. In other embodiments, the watermark comprises data
hashing files to provide tamper detection. In other embodiments,
the watermark provides copyright information about the file.
[0193] In some embodiments, the network connection information
pertains to bandwidth capabilities. In other embodiments, the
network connection information pertains to Internet Protocol
address. In still other embodiments, the network connection
information consists of an Internet Protocol address. In one
embodiment, the network connection information comprises a network
zone identifying the logon agent to which the client 102 provided
authentication credentials.
[0194] In some embodiments, the authorization credentials include a
number of types of authentication information, including without
limitation, user names, client names, client addresses, passwords,
PINs, voice samples, one-time passcodes, biometric data, digital
certificates, tickets, etc. and combinations thereof. After
receiving the gathered information 612, the policy engine 236 makes
an access control decision based on the received information
612.
[0195] Referring now to FIG. 6B, a block diagram depicts one
embodiment of a policy engine 236, including a first component 620
comprising a condition database 622 and a logon agent 624, and
including a second component 630 comprising a policy database 632.
The first component 620 applies a condition from the condition
database 622 to information received about client 102 and
determines whether the received information satisfies the
condition.
[0196] In some embodiments, a condition may require that the client
102 execute a particular operating system to satisfy the condition.
In some embodiments, a condition may require that the client 102
execute a particular operating system patch to satisfy the
condition. In still other embodiments, a condition may require that
the client 102 provide a MAC address for each installed network
card to satisfy the condition. In some embodiments, a condition may
require that the client 102 indicate membership in a particular
Active Directory to satisfy the condition. In another embodiment, a
condition may require that the client 102 execute a virus scanner
to satisfy the condition. In other embodiments, a condition may
require that the client 102 execute a personal firewall to satisfy
the condition. In some embodiments, a condition may require that
the client 102 comprise a particular device type to satisfy the
condition. In other embodiments, a condition may require that the
client 102 establish a particular type of network connection to
satisfy the condition.
[0197] If the received information satisfies a condition, the first
component 620 stores an identifier for that condition in a data set
626. In one embodiment, the received information satisfies a
condition if the information makes the condition true. For example,
a condition may require that a particular operating system be
installed. If the client 102 has that operating system, the
condition is true and satisfied. In another embodiment, the
received information satisfies a condition if the information makes
the condition false. For example, a condition may address whether
spyware exists on the client 102. If the client 102 does not
contain spyware, the condition is false and satisfied.
[0198] In some embodiments, the logon agent 624 resides outside of
the policy engine 236. In other embodiments, the logon agent 624
resides on the policy engine 236. In one embodiment, the first
component 620 includes a logon agent 624, which initiates the
information gathering about client 102. In some embodiments, the
logon agent 624 further comprises a data store. In these
embodiments, the data store includes the conditions for which the
collection agent may gather information. This data store is
distinct from the condition database 622.
[0199] In some embodiments, the logon agent 624 initiates
information gathering by executing the collection agent 304. In
other embodiments, the logon agent 624 initiates information
gathering by transmitting the collection agent 304 to the client
102 for execution on the client 102. In still other embodiments,
the logon agent 624 initiates additional information gathering
after receiving information 612. In one embodiment, the logon agent
624 also receives the information 612. In this embodiment, the
logon agent 624 generates the data set 626 based upon the received
information 612. In some embodiments, the logon agent 624 generates
the data set 626 by applying a condition from the database 622 to
the information received from the collection agent 304.
[0200] In another embodiment, the first component 620 includes a
plurality of logon agents 624. In this embodiment, at least one of
the plurality of logon agents 624 resides on each network domain
from which a client 102 may transmit a resource request. In this
embodiment, the client 102 transmits the resource request to a
particular logon agent 624. In some embodiments, the logon agent
624 transmits to the policy engine 236 the network domain from
which the client 102 accessed the logon agent 624. In one
embodiment, the network domain from which the client 102 accesses a
logon agent 624 is referred to as the network zone of the client
102.
[0201] The condition database 622 stores the conditions that the
first component 620 applies to received information. The policy
database 632 stores the policies that the second component 630
applies to the received data set 626. In some embodiments, the
condition database 622 and the policy database 632 store data in an
ODBC-compliant database. For example, the condition database 622
and the policy database 632 may be provided as an ORACLE database,
manufactured by Oracle Corporation of Redwood Shores, Calif. In
other embodiments, the condition database 622 and the policy
database 632 can be a Microsoft ACCESS database or a Microsoft SQL
server database, manufactured by Microsoft Corporation of Redmond,
Wash.
[0202] After the first component 620 applies the received
information to each condition in the condition database 622, the
first component transmits the data set 626 to second component 630.
In one embodiment, the first component 620 transmits only the data
set 626 to the second component 630. Therefore, in this embodiment,
the second component 630 does not receive information 612, only
identifiers for satisfied conditions. The second component 630
receives the data set 626 and makes an access control decision by
applying a policy from the policy database 632 based upon the
conditions identified within data set 626.
[0203] In one embodiment, policy database 632 stores the policies
applied to the received information 612. In one embodiment, the
policies stored in the policy database 632 are specified at least
in part by the system administrator. In another embodiment, a user
specifies at least some of the policies stored in the policy
database 632. The user-specified policy or policies are stored as
preferences. The policy database 632 can be stored in volatile or
non-volatile memory or, for example, distributed through multiple
servers.
[0204] In one embodiment, a policy allows access to a resource only
if one or more conditions are satisfied. In another embodiment, a
policy allows access to a resource but prohibits transmission of
the resource to the client 102. Another policy might make
connection contingent on the client 102 that requests access being
within a secure network. In some embodiments, the resource is an
application program and the client 102 has requested execution of
the application program. In one of these embodiments, a policy may
allow execution of the application program on the client 102. In
another of these embodiments, a policy may enable the client 102 to
receive a stream of files comprising the application program. In
this embodiment, the stream of files may be stored and executed in
an isolation environment. In still another of these embodiments, a
policy may allow only execution of the application program on a
server 106, such as an application server, and require the server
106 to transmit application-output data to the client 102.
[0205] Referring now to FIG. 6C, a flow diagram depicts one
embodiment of the steps taken by the policy engine 236 to make an
access control decision based upon information received about a
client 102. Upon receiving gathered information about the client
102 (Step 650), the policy engine 236 generates a data set based
upon the information (Step 652). The data set 626 contains
identifiers for each condition satisfied by the received
information 612. The policy engine 236 applies a policy to each
identified condition within the data set 626. That application
yields an enumeration of resources which the client 102 may access
(Step 654). The policy engine 236 then presents that enumeration to
the client 102. In some embodiments, the policy engine 236 creates
a Hypertext Markup Language (HTML) document used to present the
enumeration to the client.
[0206] In some embodiments, a determination is made as to a type of
connection to establish when granting access to a resource
responsive to a determination by a policy engine such as the policy
engine 236 described above in FIG. 6A, FIG. 6B and FIG. 6C. In
other embodiments, a determination is made as to a method for
granting access to a resource, such as a method for execution,
responsive to a determination by a policy engine such as the policy
engine 236 described above in FIG. 6A, FIG. 6B and FIG. 6C. In
other embodiments, the server 106 or appliance 200 receiving the
credentials and the request to execute the enumerated application
further comprises such a policy engine 236.
[0207] In one embodiment, one of a plurality of types of access is
identified, responsive to a policy, each of the plurality of types
of access associated with at least one connection characteristic.
In one embodiment, the identification is made responsive to an
application of a policy to the received credentials associated with
the client 102. In some embodiments, the selection is made by a
policy engine such as the policy engine 236 described above in FIG.
6A, FIG. 6B and FIG. 6C. In other embodiments, the server 106 or
appliance 200 receiving the credentials and the request to execute
the enumerated application further comprises such a policy engine
236.
[0208] In some embodiments, after a server 106 or appliance 200
authorizes access to a resource, a client 102 performs a pre-launch
analysis of the client 102. In one of these embodiments, the client
102 performs the pre-launch analysis to confirm authorization to
access a resource, or to complete the authorization process. In
other embodiments, the client 102 performs a pre-launch analysis of
the client 102 prior to the authorization decision. In still other
embodiments, the client 102 performs a pre-launch analysis of the
client 102 after receiving authorization to access a resource but
prior to the establishment of a connection to the resource. In one
of these embodiments, the client 102 performs a pre-launch analysis
of the client 102 after receiving authorization to access a
resource but prior to an identification of a type of connection
authorized for use in accessing the resource.
[0209] In one embodiment, the client 102 performs the pre-launch
analysis prior to retrieving and executing a resource, such as a
plurality of application files comprising an application program.
In another embodiment, the client 102 performs the pre-launch
analysis responsive to a received indication that the pre-launch
analysis is a requirement for authorization to access a resource,
such as the plurality of application files comprising an
application program. In still another embodiment, the client 102
retrieves at least one characteristic required for execution of an
application program. In yet another embodiment, the client 102
receives access information indicating a location of a file for
retrieval by the client 102, the file enumerating the at least one
characteristic. In some embodiments, the client 102 performs the
pre-launch analysis after a server 106 or appliance 200 selects a
method of providing access to a resource and identifying a type of
connection to establish between the client and the resource.
[0210] The client 102 determines the existence of the at least one
characteristic on the client 102. In some embodiments, the client
102 makes this determination as part of the pre-launch analysis. In
one embodiment, determining the existence of the at least one
characteristic on the client 102 includes determining whether a
device driver is installed on the client 102. In another
embodiment, determining the existence of the at least one
characteristic on the client 102 includes determining whether an
operating system is installed on the client 102. In still another
embodiment, determining the existence of the at least one
characteristic on the client 102 includes determining whether a
particular operating system is installed on the client 102. In yet
another embodiment, determining the existence of the at least one
characteristic on the client 102 includes determining whether a
particular revision level of an operating system is installed on
the client 102.
[0211] In some embodiments, determining the existence of the at
least one characteristic on the client 102 includes determining
whether the client 102 has acquired authorization to execute an
enumerated application. In one of these embodiments, a
determination is made by the client 102 as to whether the client
102 has received a license to execute the enumerated application.
In another of these embodiments, a determination is made by the
client 102 as to whether the client 102 has received a license to
receive across an application streaming session a plurality of
application files comprising the enumerated application. In other
embodiments, determining the existence of the at least one
characteristic on the client 102 includes determining whether the
client 102 has sufficient bandwidth available to retrieve and
execute an enumerated application.
[0212] In some embodiments, determining the existence of the at
least one characteristic on the client 102 includes execution of a
script on the client 102. In other embodiments, determining the
existence of the at least one characteristic on the client 102
includes installation of software on the client 102. In still other
embodiments, determining the existence of the at least one
characteristic on the client 102 includes modification of a
registry on the client 102. In yet other embodiments, determining
the existence of the at least one characteristic on the client 102
includes transmission of a collection agent 304 to the client 102
for execution on the client 102 to gather credentials associated
with the client 102.
[0213] In some embodiments, the client 102 makes a request for
authorization to execute an application responsive to a
determination that at least one characteristic exists on the client
102. In one of these embodiments, the client 102 determines that a
plurality of characteristics exist on the client 102, the plurality
of characteristics associated with an enumerated application and
received responsive to a request to execute the enumerated
application. In another of these embodiments, whether the client
102 receives authorization for execution of the enumerated
application files depends upon existence of the at least one
characteristic on the client 102. In one embodiment, the client 102
received an enumeration of application programs, requested
execution of an enumerated application, and received access
information including the at least one characteristic and a launch
ticket authorizing the execution of the enumerated application upon
the determination of the existence of the at least one
characteristic on the client 102. In some embodiments, the client
102 executes a second client agent 120', the second client agent
120' requesting execution of an application on a server 106,
responsive to a determination that the client 102 lacks the at
least one characteristic.
[0214] Referring now to FIG. 7, a block diagram depicts one
embodiment of a system for authorizing a level of access of a
client to a virtual private network connection based on a
client-side attribute. In brief overview, the system includes a
client 102, a means for transmitting a request 702, a request 704,
an evaluation component 706, a means for transmitting a response
708, a means for receiving an authorization assignment 710, and an
appliance 200.
[0215] The means for transmitting a request 702 transmits from the
client 102 to the appliance 200 the request for a virtual private
network connection to a network. In one embodiment, the means for
transmitting a request 702 comprises a transmitter. In another
embodiment, the means for transmitting a request 702 resides in the
client agent 120. In one embodiment, the means for transmitting a
request 702 transmits a request for access to a resource, such as
an application or server 106, residing on the network. In another
embodiment, the means for transmitting a request 702 transmits a
request for a network address on the virtual private network. In
still another embodiment, the means for transmitting a request 702
transmits the request for the virtual private network connection
after authenticating the client 102 to the appliance 200. In yet
another embodiment, the means for transmitting a request 702
transmits the request prior to the establishment of a control
connection. In a further embodiment, the appliance 200 establishes
the control connection responsive to receiving the request from the
client 102.
[0216] The request 704 is received by the client 102, via a control
connection between the client 102 and the appliance 200, for
evaluation of at least one clause of a security string, the at
least one clause identifying an object for evaluation, an attribute
of the object, and a pre-requisite associated with the attribute.
In one embodiment, the request 704 includes at least one clause of
a security string, the at least one clause identifying the client
as an object for evaluation. In another embodiment, the request 704
includes at least one clause of a security string, the at least one
clause identifying a presence of an application program on the
client as an attribute of the object. In still another embodiment,
the request 704 includes at least one clause of a security string,
the at least one clause identifying an absence of an application
program on the client as an attribute of the object. In yet another
embodiment, the request 704 includes at least one clause of a
security string, the at least one clause identifying a presence of
a version of an application program on the client as an attribute
of the object.
[0217] In one embodiment, the request 704 includes at least one
clause of a security string, the at least one clause identifying an
absence of a version of an application program on the client as an
attribute of the object. In another embodiment, the request 704
includes at least one clause of a security string, the at least one
clause identifying a presence of a required version of an
application program on the client as a pre-requisite. In still
another embodiment, the request includes at least one clause of a
security string, the at least one clause identifying a presence of
an application program on the client as a pre-requisite. In yet
another embodiment, the request includes at least one clause of a
security string, the at least one clause identifying an absence of
an application program on the client as a pre-requisite. In some
embodiments, the request 704 is sent to the client 102 over the
control connection in response to a request by the client for
access to a resource or initiation of a connection.
[0218] In some embodiments, the kernel on the client 102 receives a
security string. In one of these embodiments, the kernel identifies
one or more atomic expressions within the security string. In
another of these embodiments, the atomic expressions within the
security string are separated by logical operators. The logical
operators may be expressed by, for example, double ampersands
indicating that the expressions are conjunctive or double slashes
indicating that the expressions are disjunctive. In still another
of these embodiments, the at least one clause of the security
string is an atomic expression within the security string separated
from other expressions in the security string by logical operators.
In other embodiments, and as shown in shadow in FIG. 7, the kernel
on the client 102 comprises receiver for receiving the request 704
from the appliance 200 over the control channel. In one of these
embodiments, the kernel transmits all or part of the request to the
evaluation component 706.
[0219] In one embodiment, a user of an appliance 200 generates the
security string. In another embodiment, the appliance 200 adds a
generated security string as a policy. In still another embodiment,
the appliance 200 adds a generated security string as a policy
within an authorization server, a policy engine, a firewall, a
virtual private network server, or other security appliance. In
some embodiments, the appliance 200 transmits the generated
security string to the client 102 in its entirety and without
re-formatting from the form in which the security string was
generated. In other embodiments, the appliance 200 transmits only
portions of the security string to the client 102, such as one
clause or atomic expression at a time. In still other embodiments,
the appliance 200 transmits the generated security string to a
kernel on the client 102 for formatting and parsing into atomic
expressions.
[0220] In one embodiment, a security string is associated with an
authorization group. In another embodiment, if a client 102
satisfies a requirement expressed by the security string, the
client 102 is assigned to the authorization group. In still another
embodiment, if a client 102 fails to satisfy a requirement
expressed by the security string, the client 102 is assigned to the
authorization group. In some embodiments, if no security string is
assigned to an authorization group, the client 102 request is
granted without the need for evaluation of a security string. In
other embodiments, if no authorization group is assigned to a
security string, but evaluation of the security string is required
by the appliance 200, the client 102 request is denied.
[0221] In one embodiment, a security string is an expression of a
policy. In another embodiment, and as an example, if a policy
requires a client 102 to execute a particular personal firewall
program or a particular antivirus program before accessing a
resource or a establishing a type of connection, and if the policy
assigns the client to a particular authorization group if the
client fails to satisfy the policy, a security string expressing
the policy may be of the form:
"pf.sub.--1_ZoneAlarm.sub.--4.0.012.013.parallel.pf.sub.--1_TrendMicro.su-
b.--11.0.0"-clientsecurityAuthGroup ag2." In still another
embodiment, and as a second example, a policy may require a
particular revision level of an antivirus program and a particular
process running, and if the policy assigns the client to a
particular authorization group if the client fails to satisfy the
policy, a security string expressing the policy may be of the form:
"av.sub.--0_mcafeevirusscan.sub.--4.88 &&
svc.sub.--0_svchost"-clientsecurityAuthGroup ag1."
[0222] In some embodiments, a priority level may be assigned to the
security string. In one of these embodiments, the appliance 200 may
transmit the security string having the highest priority to the
client 102. In another of these embodiments, and as an example, if
the appliance 200 identifies the following two security
strings:
TABLE-US-00005 sal -clientsecurity "av_0_mcafeevirusscan_4.88
&& svc_0_svchost" - cliensecurityAuthGroup ag1 sa2
-clientsecurity "pf_1_ZoneAlarm_4.0.012.013 ||
pf_1_TrendMicro_11.0.0" - clientsecurityAuthGroup ag2,
the appliance 200 may select the higher priority security string
(sa1) over the lower priority string (sa2). In still another of
these embodiments, when a client 102 connects to a vServer 275 on
the appliance 200, the appliance 200 evaluates applicable security
strings and identifies the security string to transmit to the
client 102.
[0223] In other embodiments, a security string may be expressed in
the form "object.attribute.prerequisite." In one of these
embodiments, and for example, the security string may be an
expression identifying the client 102, a particular application
program associated with the client 102 and a prerequisite
associated with the program, the expression having the following
form:
TABLE-US-00006 client.application[mcafeevirusscan].version >=
4.88 && client.svc[svchost]RUNNING
In this embodiment, the object is the client 102 (client), the
attribute is an antivirus program (application[mcafeevirusscan]),
and the pre-requisite is that the application be of at least a
particular version level (version>=4.88). In this embodiment,
the security string comprises two clauses and the second clause
identifies the client 102, a process on the client (a service
called svchost), and a pre-requisite associated with the process
(that the svchost process be executing, or running, on the client).
In this embodiment, the double ampersand indicates that the client
must satisfy both of the clauses to satisfy the security
string.
[0224] In another of these embodiments, and as a second example,
the security string may comprise an expression having two
disjunctive clauses in which the client 102 may satisfy one clause
or the other to satisfy the security string. In one example of this
embodiment, the expression may be of the following form:
TABLE-US-00007 client.application.pf[ZoneAlarm].version >=
4.0.012.013 || client.application.pf[TrendMicro].version >=
11.0.0.
In this embodiment, the client 102 will satisfy the security string
if the client 102 executes a particular level of a particular
personal firewall (ZoneAlarm version 4.0.012.013 or greater) or if
the client 102 executes a particular level of a particular
antivirus program (TrendMicro version 11.0.0 or greater).
[0225] The evaluation component 706 resides on the client 102,
identifies the attribute, determines whether the attribute
satisfies the pre-requisite, and evaluates the at least one clause.
In some embodiments, the evaluation component 706 resides in the
client agent 120. In other embodiments, the kernel of the client
102 provides the functionality of the evaluation component 706. In
still other embodiments, the kernel of the client 102 validates a
response provided by the evaluation component 706.
[0226] In one embodiment, the evaluation component 706 executes a
script to evaluate the at least one clause. In another embodiment,
the evaluation component 706 is transmitted to the client 102 from
the appliance 200. In still another embodiment, the evaluation
component 706 is a collection agent, such as a collection agent 304
described above in connection with FIGS. 4A, 4B, and 4C, the
collection agent gathering information associated with the
attribute. In yet another embodiment, the evaluation component 706
evaluates the at least one clause responsive to the information
gathered about the client 102.
[0227] In some embodiments, the evaluation component 706 identifies
attributes of the client 102. In one of these embodiments, the
attributes include, but are not limited to, any of the following:
client operating system, presence of service packs, presence of hot
fixes on the client, executing services, executing processes,
presence of certain files, antivirus software, personal firewall
software, anti-spam software, internet security software, and
registry configuration. In another of these embodiments, the
attributes of the client 102 include information associated with
the client, such as the information described in connection with
the collection agent 304, described above in connection with FIG.
6A and FIG. 6B. In still another of these embodiments, the
attributes of the client 102 include information associated with
the client and gathered as part of a pre-launch analysis, as
described above.
[0228] In one embodiment, the evaluation component 706 identifies
an attribute indicating a presence on the client of one of the
following: a version of an operating system, a service pack of the
operating system, a running service, a running process, and a file.
In another embodiment, the evaluation component 706 identifies an
attribute indicating a presence on the client of one of the
following: antivirus software, personal firewall software,
anti-spam software, and internet security software. In still
another embodiment, the evaluation component 706 identifies an
attribute identifying a version of one of the following: antivirus
software, personal firewall software, anti-spam software, and
internet security software. In yet another embodiment, the
evaluation component 706 determines that the attribute satisfies
the pre-requisite responsive to the identification of the
attribute.
[0229] In some embodiments, as described above, the client 102
performs the pre-launch analysis after a server 106 or appliance
200 selects a method of providing access to a resource and
identifying a type of connection to establish between the client
and the resource. In other embodiments, the client 102 performs a
pre-launch analysis of the client 102 prior to an authorization
decision by the appliance 200. In other embodiments, the client 102
performs a pre-launch analysis of the client 102 after receiving
authorization to access a resource but prior to the establishment
of a connection to the resource. In one of these embodiments, the
client 102 performs a pre-launch analysis of the client 102 after
receiving authorization to access a resource but prior to an
identification of a type of connection authorized for use in
accessing the resource.
[0230] In some embodiments depicted by FIG. 6A and FIG. 6B, the
client 102 performs a pre-launch analysis prior to the
identification of a type of connection to establish between the
client and the resource. In one of these embodiments, the client
102 transmits a result of the pre-launch analysis to the appliance
200. In another of these embodiments, the appliance 200 makes an
access control decision, including an identification of a type of
connection to establish between the client 102 and a requested
resource, responsive to a received result of a pre-launch analysis.
In other embodiments, the client 102 evaluates a security string as
part of a pre-launch analysis. In still other embodiments, the
client 102 transmits a result of a pre-launch analysis to a kernel
on the client 102. In yet other embodiments, the kernel evaluates a
security string responsive to a received result of the pre-launch
analysis.
[0231] In some embodiments, the kernel on the client 102 receives
the security string. In one of these embodiments, the kernel
identifies a plurality of clauses in the security string, the
clauses separated by logical operators. In another of these
embodiments, the clauses within the string are atomic expressions.
In still another of these embodiments, the kernel transmits at
least one clause to the evaluation component 706 for evaluation,
the at least one clause comprising an atomic expression. In yet
another of these embodiments, the evaluation component 706
transmits a result of evaluating the atomic expression to the
kernel.
[0232] In other embodiments, the kernel on the client 102 receives
a result of an evaluation of at least one clause in the security
string from the evaluation component 706. In one of these
embodiments, the kernel on the client 102 evaluates a security
string comprising a plurality of clauses responsive to receiving a
plurality of results from the evaluation component 706. In another
of these embodiments, the kernel on the client 102 comprises the
means for transmitting a response 708. In still another of these
embodiments, the kernel on the client 102 transmits a result of an
evaluation of an entire security string, comprising a plurality of
clauses, to the appliance 200.
[0233] The means for transmitting a response 708 transmits from the
client 102 to the appliance 200, via the control connection, a
response comprising a result of the evaluation of the at least one
clause by the evaluation component 706. In one embodiment, the
means for transmitting a response 708 transmits a packet to the
appliance 200 with the result of the evaluation. In another
embodiment, the means for transmitting a response 708 transmits a
"1" if the client satisfies the at least one clause or a "0" if the
client does not satisfy the at least one clause. In some
embodiments, the means for transmitting a response 708 resides on
the evaluation component 706. In other embodiments, the means for
transmitting a response 708 resides in the client agent 120. In
still other embodiments, the means for transmitting a response 708
comprises a transmitter residing in the client agent 120 and
sending packets over the control channel.
[0234] The means for receiving an authorization assignment 710
receives from the appliance 200 at the client 102 an assignment to
an authorization group, the assignment determined based on the
evaluation of the at least one clause. In one embodiment, the means
for receiving the authorization assignment 710 receives an
assignment made responsive to the result of evaluation of a second
clause by the appliance 200. In another embodiment, the means for
receiving the authorization assignment 710 receives an assignment
made responsive to a determination by the appliance 200 that the
client 102 lacks a desired attribute. In still another embodiment,
the means for receiving the authorization assignment 710 receives
an assignment to an authorization group providing quarantined
access to the network via the appliance 200.
[0235] In some embodiments, the means for receiving an
authorization assignment 710 comprises a component residing in the
client agent 120. In other embodiments, the means for receiving an
authorization assignment 710 resides in a kernel on the client 102.
In still other embodiments, the means for receiving an
authorization assignment 710 comprises a receiver in communication
with the appliance 200.
[0236] In some embodiments, an authorization group to which a user
of a client 102 belongs is identified by an evaluation of the
client 102 and of attributes of the client 102. In one of these
embodiments, a user of a client 102 requesting access to a network
or other resource, or requesting a connection to a network or a
resource on the network, is a member of a group of users, each
member in the group authorized to access particular resources via
particular types of connections. In another of these embodiments, a
user of a client 102 belongs to a default authorization group. In
still another of these embodiments, the appliance 200 evaluates the
client 102 and determines that although the user of the client 102
is a member of a particular authorization group, the user does not
currently satisfy the requirements for membership in the group, and
is therefore not authorized to access the resources that the user
is typically authorized to use. Alternatively, the appliance 200
may evaluate the client 102 and determine that although the user is
not authorized to access particular resources via one type of
connection, the client 102 may connect via a different type of
connection. In yet another embodiment, the appliance 200 may
evaluate the client 102 and determine that although the user is not
authorized to access a particular set of resources, the client 102
may access a subset of those resources via a particular type of
connection, such as via a secure connection to a quarantined
network. In some embodiments, an authorization group may be created
for the user of the client 102 upon the evaluation of the
attributes of the client 102. In other embodiments, the client 102
satisfies the requirements of the applicable security strings and a
connection is established according to the rules or policies of the
client 102's default authorization group.
[0237] In one embodiment, the means for receiving the authorization
assignment 710 receives a denial, from the appliance 200, of the
client request if the security string is not associated with an
authorization group. In another embodiment, the means for receiving
the authorization assignment 710 receives a denial, from the
appliance 200, of the client request if a pre-requisite in the
security string is not satisfied. In still another embodiment, the
means for receiving the authorization assignment 710 receives an
assignment made responsive an evaluation, by the appliance 200, of
a second clause of the security string comprising one or more
logical operations.
[0238] Referring now to FIG. 8, a flow diagram depicts one
embodiment of the steps taken in a method for authorizing a level
of access of a client to a virtual private network connection based
on a client-side attribute. In brief overview, an appliance
establishes a control connection with a client upon receiving a
client request to establish a virtual private network connection
with a network (step 802). The appliance transmits, via the control
connection, a request to the client to evaluate at least one clause
of a security string, the at least one clause including an
expression associated with a client-side attribute (step 804). The
client transmits, via the control connection, a response to the
appliance comprising a result of evaluating the at least one clause
by the client (step 806). The appliance assigns the client to an
authorization group based on the result of evaluation of the at
least one clause (step 808).
[0239] Referring now to FIG. 8, and in greater detail, an appliance
establishes a control connection with a client upon receiving a
client request to establish a virtual private network connection
with a network (step 802). In one embodiment, the appliance
receives a request from the client to access a resource on a
network, such as a file or application. In another embodiment, the
appliance receives a request from the client to access a server
106. In still another embodiment, the appliance receives a request
for an association between the client and a network address
associated with the virtual private network. In yet another
embodiment, the client initiates establishment of the control
connection. In some embodiments, the appliance is an appliance 200
as described above.
[0240] The appliance transmits, via the control connection, a
request to the client to evaluate at least one clause of a security
string, the at least one clause including an expression associated
with a client-side attribute (step 804). In one embodiment, the
appliance transmits the request to a collection agent on the
client, such as a collection agent 304 described above, the
collection agent gathering information associated with the
client-side attribute and evaluating the at least one clause. In
another embodiment, the appliance transmits a script to the client
for execution. In still another embodiment, the appliance transmits
a collection agent to the client, the collection agent evaluating
the at least one clause.
[0241] The client transmits, via the control connection, a response
to the appliance comprising a result of evaluating the at least one
clause by the client (step 806). In one embodiment, the client
evaluates the at least one clause. In another embodiment, a
collection agent or evaluation component on the client evaluates
the at least one clause. In still another embodiment, the client
evaluates the at least one clause by executing a script. In yet
another embodiment, the client gathers information associated with
the client-side attribute. In a further embodiment, the client
evaluates the at least one clause responsive to the gathered
information.
[0242] In one embodiment, the client identifies a client-side
attribute indicating a presence on the client of one of the
following: a version of an operating system, a service pack of the
operating system, a running service, a running process, and a file.
In another embodiment, the client identifies a client-side
attribute indicating a presence on the client of one of the
following: antivirus software, personal firewall software,
anti-spam software, and internet security software. In still
another embodiment, the client identifies a client-side attribute
indicating a version on the client of one of the following:
antivirus software, personal firewall software, anti-spam software,
and internet security software.
[0243] In one embodiment, the appliance evaluates a second clause
of the security string. In another embodiment, the appliance
evaluates a clause of the security string comprising one or more
logical operations. In some embodiments, the appliance receives
gathered information associated with the client. In one of these
embodiments, the appliance receives the gathered information from a
collection agent, such as a collection agent 304 executing on the
client 102 as described above. In another of these embodiments, the
appliance evaluates the second clause of the security string
responsive to the gathered information.
[0244] The appliance assigns the client to an authorization group
based on the result of evaluation of the at least one clause (step
808). In one embodiment, the appliance determines that the client
lacks a desired client-side attribute, responsive to the result of
the evaluation of the at least one clause. In another embodiment,
the appliance assigns the client to an authorization group
providing quarantined access to the network via the appliance. In
still another embodiment, the appliance configures an authorization
policy comprising the security string. In yet another embodiment,
the appliance assigns the authorization policy to the authorization
group.
[0245] In one embodiment, the appliance denies a login request from
a client if the security string is not associated with the
authorization group. In another embodiment, the appliance
establishes a virtual private network connection with the client in
accordance with the authorization group. In still another
embodiment, the appliance establishes a virtual private network
connection between the client and a server residing on a virtual
private network.
[0246] In one embodiment, the appliance assigns the client to an
authorization group based on an application of a policy to the
result of evaluation of the at least one clause. In another
embodiment, the appliance transmits the response comprising the
result of the evaluation to a policy engine. In still another
embodiment, the appliance assigns the client to an authorization
group based on an application of a policy by the policy engine.
G. Appliance Failover Environment
[0247] Referring now to FIG. 9, an embodiment of an environment for
providing session failover between multiple appliances 200 is
depicted. In brief overview, a first appliance 200, referred to as
a primary appliance, may provide session connectivity between a
client and a network 104, such as to a server, on behalf of a user.
For example, the first appliance 200 may establish as SSL VPN
session 905 between the client and a server. A second appliance
200' referred to as a secondary, backup or failover appliance acts
as a failover or backup to the first appliance 200 for providing
session connectivity for the client 102 to a network, or a server,
such as via an SSL VPN session. Upon detection of failure of the
primary appliance 200 in providing session connectivity or network
access, the second appliance 200' becomes the primary appliance 200
to provide connectivity or access for the client via the
session.
[0248] The primary appliance 200 sends, transmits, shares or
otherwise provides information to the secondary appliance 200' via
a connection or communication channel referred to as a session
failover connection 930. The primary appliance 200 may communicate
with the secondary appliance 200' using any type and form of
protocol or protocols via the connection 930. In one embodiment,
the primary appliance 200 makes RPC (remote procedure calls) via a
TCP or UDP connection. In other embodiments, the primary appliance
200 and secondary appliance 200' may communicate using any type and
form of custom or proprietary protocol. In some embodiments, the
connection 930 includes a secure, tunneled, encrypted or virtual
private network connection, and any type and form of protocols
thereof. For the example, the connection 930 may include a VPN or
SSL VPN connection. In yet another embodiment, the appliance 200
and 200' may communicate via a plurality of session failover
connections 930. In other embodiments, the appliances may multiple
a plurality of SSL VPN session information and communications via
one or more connections 930.
[0249] The primary appliance 200 may establish the connection 930
with the secondary appliance 200' or the secondary appliance 200'
may establish the connection 930 with the primary appliance 200.
The connection 930 may be established at any time during operations
of the appliances 200, 200'. In one embodiment, the appliances
establish the connection 930 upon startup of either the primary or
secondary appliance. In another embodiment, the appliances
establish the connection 930 upon initiation or during the setup of
a session. In some embodiments, the appliances establish the
connection 930 in response to a command received from a user,
system or application. For example, in one case, the appliances
establish the connection response to configuration information
received from a user. In another embodiment, the appliances
establish the connection 930 in response to triggering or
applications of one or more policies of a policy engine 236.
[0250] A session manager 915 may include any software, hardware or
any combination of software and hardware. The session manager 915
may include any type and form of program, service, task, process or
executable instructions operating in user mode 202, kernel mode 204
or any combination thereof in the appliance 200. In some
embodiments, the session manager is a vServer 275, or a portion
thereof, as depicted and described in conjunction with FIG. 2B. For
example, a vServer 275 includes any logic, functions, rules, or
operations to perform any embodiments of the session management
techniques described herein, such as SSL VPN session management. In
some embodiments, the session manager 915 provides or otherwise
supports any of the SSL VPN functionality 280, and any embodiments
thereof, described in connection with FIG. 2B above.
[0251] As also previously described herein in connection with FIG.
4, the appliance 200 may host one or more intranet internet
protocol or intranetIP or IIP addresses 282A-282N. The appliance
200 may associate and assign these IIP addresses 282 with a user
and/or client For example, when connected from a first network 104
to a second network 104' via the appliance 200, the appliance 200
establishes, assigns or otherwise provides an IntranetIP address
for the user and/or client 102 on the second network 104'. The
appliance 200 listens for and receives on the second or private
network 104' for any communications directed towards the client 102
using the client's established IntranetIP 282. In one embodiment,
the appliance 200 acts as or on behalf of the client 102 on the
second private network 104. The appliance 200 may forward to the
client 102 communications from the second network 104' directed
towards the IIP address 282.
[0252] The appliance 200 and/or 200' may have a session propagator
910 including software, hardware or any combination of software and
hardware. The session propagator 910 may include logic, functions,
operations or executable instructions, such as a program, service
or task to propagate a session or any information thereof between
appliances. The session propagator 910 may transmit information of
one or more sessions via the session failover connection. The
information may include any data identify or specify any one or
more of the following: 1) identifier for the session, 2) type of
session, 3) configuration of session, 4) type or name of
application for the session, 5) the computing devices participating
in the session, such as network identifiers for the devices, 6) any
IIP addresses for the session or users, such as IIP Pool 410, 7)
IIP policies 420, 8) IPLWDB 450 (see FIG. 4), 9) any users
associated with the session 10) any policies used for the session,
such as names of SSL VPN policies, 11) any end point authorization
policies, such as client security strings used for the session, 12)
session state, and/or 13) any session metrics, such as length of
the session.
[0253] In one embodiment, the primary appliance 200 propagates or
synchronizes policies with the secondary appliance 200'. In some
embodiments, the policy configuration of the primary appliance 200
is distributed and used in the secondary appliance 200'. In other
embodiments, the primary and secondary appliances are configured
with the same policies or with the same policies applicable to
sessions to be handled via failover by the secondary appliance
200'. In another embodiment, the secondary appliance 200' maintains
and uses one or more different policies on a failover session.
[0254] The session propagator 910 may propagate information for one
or more sessions in any form, including one or more objects, data
structures, or files. The appliance 200 and/or session propagator
910 may packetize any of this information into one or more network
packets and payloads thereof in a manner in accordance with the
protocols used between the appliances. In some embodiments, a first
propagator 910 on a first appliance 200 communicate or interfaces
to a second propagator 910 on a second appliance 200 to provide
session information, such as information for the second appliance
200' to create, generate or otherwise establish the session 905 on
the second appliance 200' as exists on the first appliance 200.
[0255] The session propagator 910 may propagate a session based on
one or more policies. For example, in one embodiment, the policy
engine 236 may have an SSL VPN session applied to a session that
indicates the session is not have a failover or backup session. In
some cases, a first set of one or more sessions may be propagated
from one appliance to another appliance, while a second set of one
or more sessions are not propagated between appliances.
[0256] The session propagator 910 may propagate a session from one
appliance to another appliance synchronously or asynchronously. The
session propagator 910 may propagate a session during a sequence of
operations of establishing a session, such as an SSL VPN session,
on the primary appliance 200. By way of example, the primary
appliance 200 may received a request from a client to establish a
connection with a server. In response, the appliance 200 creates a
session 905 on the appliance 200. The primary appliance 200 may
apply any policies to the session, such as any configured SSL VPN
policies may be applied to the session. Upon creation or
establishment of the session, the primary appliance 200 via the
session propagator 910 propagates the session to the secondary
appliance 200. The secondary appliance 200' may establish the
second session via the session manager 915 and/or session
propagator 910 of the secondary appliance 200'. This may be
referred to as a failover or backup session.
[0257] In one embodiment, some portions or information of the
session may change dynamically during the course of using the
session or during the lifetime of the session. For example, the
appliance 200 and/or session manager 915 may maintain counters for
auditing and/or to maintain session statistics. These counters may
change dynamically during operation or lifetime of the session. In
some embodiments, the session propagator 915 propagates these
dynamically changing session information upon the change in the
session. In other embodiments, the session propagator 915
propagates session information, including changed session
information, on a predetermined frequency or time period. In yet
another embodiment, the session propagator 915 propagates session
information, including changed session information, triggered by
predetermined events. In some embodiments, a first propagator 910
such as a propagator on the secondary appliance 200' queries a
second propagator 910 such as a propagator on the primary appliance
200 on a predetermined basis, such as frequency, time or event
based.
[0258] Upon receipt of session information propagated from the
primary appliance 200, the secondary appliance 200' may store this
information in memory or to storage. In one embodiment, the
secondary appliance 200' and/or session propagator 910 of the
secondary appliance 200' may re-create or otherwise establish a
session on the secondary appliance based on the session information
received from the primary appliance 200. In some embodiments, the
second appliance 200' creates or modifies a session to be a copy of
the session on the first appliance. In one case, the secondary
appliance 200' provides a session having the same session
structure, information and/or configuration as the session on the
primary appliance 200. In another embodiment, the secondary
appliance 200' updates the session with information, such as
dynamic or changed session information, received from the primary
appliance 200.
[0259] The session manager 915 may identify, track, maintain,
control and/or change a state of a session, such as any of the
following states: active, inactive, disconnected, on
hold/suspended, failed, error, backup, etc. In one embodiment, the
session manager 915 may identify a session as in an active state.
In another embodiment, the session manager 915 may identify or
change a session from active to inactive. In some embodiments, the
session manager 915 may identify a session as suspended or change
the state of a session from active to suspended. In some
embodiments, the session manager 915 may change the state of a
session from suspended to active.
[0260] For example, the secondary appliance 200' may establish a
failover session 905' for an active session 905 of the primary
appliance 200. The session manager 915 of the secondary appliance
200' may identify or establish this failover session 905' as
inactive or otherwise on hold or suspended. Upon detection of a
failover in the primary appliance 200, the session manager 915 may
change the status or state of the failover session from inactive or
suspended to active. In one embodiment, the session manager 915
changes the state of the failover session to active upon
authorization of the end point, e.g., the client 102, using the
client security strings techniques described herein.
[0261] The appliance and/or session manager may control the
establishment of a session, access via a session and/or the state
of a session via any type and form of end point authentication and
authorization schemes. In some embodiment, the appliance and/or
session manager may perform any of the systems and methods of the
client security string end point authorization techniques described
above in connection with FIGS. 6A-6C, 7 and 8. For example, the
appliance 200 may transmit a client security string to the client
based on one or more polices. The client may evaluate the security
string or portion thereof and transmit the evaluation results back
to the appliance. Based on the evaluation results and/or one or
more polices, the appliance 200 may authorized the client 102 to
establish a session or to access a network, application or other
resource via the session. In some embodiments and described in
further detail below in conjunction with FIG. 11, a secondary
appliance 200 may activate a failover session upon performing
end-point scanning and authorization.
[0262] The appliance 200 and/or 200' may include a failover
detector 920. The failover detector 920 may include software,
hardware or any combination of software and hardware. The failover
detector 920 may include logic, functions, operations or executable
instructions, such as a program, service or task to determine a
status of an appliance. The failover detector 920 may determine if
an appliance is operational or running, or otherwise able to
service a connection or session 905. The failover detector 920 may
determine if a condition exists on an appliance 200, 200' such that
the management and providing of the session 905 should be
transferred from one appliance to another appliance, such as from
the primary appliance 200 to the backup appliance 200'. In one
embodiment, a failover detector 920 on appliance 200' determines
the operational status or state of the primary appliance 200. In
another embodiment, the failover detector 920 on appliance 200
determines the operational status or state of the second appliance
200'. In some embodiments, the failover detector 920 on one
appliance 200 determines the operational status or state of the
appliance 200 and forwards information on the operational
status/state to a second appliance 200', such as to a second
failover detector. In other embodiments, the failover detector 920
may be distributed among two or more appliances or on one or more
other computing devices 100. In one embodiment, the client agent
120 includes a failover detector 920.
[0263] The failover detector 920 may use any type and form of
protocol to determine a status of an appliance 200. In one
embodiment, the failover detector 920 may send any type of ping or
"heartbeat" message to an appliance to determine a status of the
appliance. In another embodiment, the failover detector 920 may
make an RPC call to determine a status of an appliance. In some
embodiments, the failover detector 920 makes an application
programming interface (API) call to determine the status of an
appliance. In yet another embodiment, the failover detector obtains
or gets status information of a appliance from a health monitoring
program, such as the health monitoring program 216 described in
conjunction with FIG. 2A.
[0264] The failover detector 920 may communicate to or interface
with the session propagator 910 and/or session manager 915 to
perform session failover upon detection of an appliance failure. In
one embodiment, the failover detector 920 transmits a message to
the session propagator 910 and/or session manager 915 to provide
notice of a failover situation or condition. In another embodiment,
the failover detector 920 triggers an event in the session
propagator 910 and/or session manager 915 to provide notice of a
failover situation or condition. In other embodiments, the failover
detector 920 makes an API call to the session propagator 910 and/or
session manager 915 to provide notice of a failover situation or
condition.
[0265] Although a single second appliance 200 is depicted in FIG.
9, a plurality of secondary appliances 200' may be deployed. For
example, a first secondary appliance 200' may be a failover
appliance for a first primary appliance 200. A second secondary
appliance 200'' may be a backup or failover appliance to the first
secondary appliance 200', and a third second appliance 200''' may
be a failover appliance for the second secondary appliance 200'',
and so on. In these embodiments, one or more sessions may be
propagated via a daisy chain of multiple failover appliances. Upon
failover of the first primary appliance 200, the first secondary
appliance 200 may become a primary appliance, such as a second
primary appliance 200. Upon failover of this second primary
appliance (or first secondary appliance, the third secondary
appliance becomes a primary appliance for the session, and so
on.
[0266] In other embodiments, a secondary appliance 200' may be a
failover or backup appliance for multiple primary appliances, such
as a first primary appliance and a second primary appliance. The
first primary appliance and the second primary appliance may each
propagate one or more session, such as SSL VPN session, to the
secondary appliance 200'. In some embodiments, a primary appliance
200 may have multiple failover secondary appliances, such as
redundant appliances. For example, a primary appliance 200 may
propagate one or more session to a first secondary appliance 200'
and a second secondary appliance 200''. In yet another embodiment,
a primary appliance 200 may propagate a first set of one or more
sessions to a first secondary appliance 200' and a second set of
one or more sessions to a second secondary appliance 200'.
[0267] The detection of failover, propagation of sessions, and/or
the transfer of the active session from a primary appliance 200 to
a secondary appliance 200' may occur seamlessly and/or
transparently to the client or user, or the applications using the
transferred session. In one embodiment, the client agent 120 is
provided notice of the failover situation and communicates with the
secondary appliance 200' instead of the primary appliance 200. In
some embodiments, the client agent 120 re-establishes a connection
and the session with the secondary appliance 200'. For example,
upon the client detecting the connection to the primary appliance
200 has been lost, dropped or otherwise disconnected, the client
agent 120 connects to the backup appliance 200'.
[0268] In other embodiments, the secondary appliance 200 after
failover has the same network identifier or IP address as the
primary appliance. In these embodiments, the client agent 120 may
communicate to the same network identifier of an appliance but the
secondary appliance 200' receives the communication instead of the
primary appliance 200. In some embodiments, the primary appliance
200 intercepts communications between the client and a server. Upon
detection of failover in these embodiments, the secondary appliance
200' intercepts the communications instead of the primary appliance
200.
[0269] The appliance 200, 200' may also include a restoration
mechanism or restorer 945 for restoring or addressing any
synchronization issues of a user's IIP address between appliances
due to an error, failure or issue with session propagation. The
restorer 945 may include software, hardware or any combination of
software and hardware. The restorer 945 may be an application,
program, library, service, process, task, thread or any other type
and form of executable instructions. The restorer 945 may include
recovery logic, function or operations to determine if an IIP
address is not synchronized or if there was an error in
propagation, and to update the appliance with the appropriate IIP
addresses and states thereof. In one embodiment, the restorer 945
queries another appliance to obtain updated IIP address and state
information for an entity, such as a user. In some embodiment, the
restorer 945 uses any type and form of address resolution protocol
(ARP), such as a gratuitous ARP, to resolve IIP address issues or
conflicts.
H. Maintaining IIP Address Stickiness Via Failover
[0270] Referring now to FIG. 10, an embodiment of steps of a method
for maintaining IIP address stickiness during appliance failover of
an SSL VPN session is depicted. Using the techniques discussed
herein, one of the one or more IIP addresses assigned to a user
and/or client in the primary appliance 200 may be used as the IIP
address for the user and/or client after failover in the secondary
appliance 200'. In this manner, although a failover condition
occurred, the SSL VPN connection may seamlessly and/or
transparently continue using the IIP address of the user and/or the
client. In other situations, when a user connects via the secondary
appliance 200', the user is assigned an IIP address that was
assigned to the user via the primary appliance 200.
[0271] In brief overview of method 1000, at step 1005, an SSL VPN
session is established for a user with a first or primary appliance
200. The appliance 200 assigns the user an IIP address for the
session. At step 1010, the primary appliance propagates SSL VPN
session to a secondary appliance 200'. The propagated information
may include one or more IIP addresses 282 assigned to or associated
with the user, such as a pool of IIP addresses 410 as depicted in
and described with FIG. 4. The secondary appliance 200' may
establish a failover session. At step 1015, a failover condition of
the primary appliance 200 is detected. At step 1020, the secondary
appliance 200 receives a request from a client to establish a
second SSL VPN session for the user. At step 1025, the secondary
appliance assigns to the user and/or client a propagated IIP
address of the user.
[0272] In further details, at step 1005, an application or a user
on the client 102 may request a SSL VPN connection from a first
network 104 to a second network 104' such as to a server 106 on
network 104. In one embodiment, the client agent 120 transmits a
request to the appliance 200 to establish the SSL VPN session with
the server 106. In some embodiments, the appliance 200 establishes
a first transport layer connection with the client 102 via client
120. In response to the request, the appliance 200 may establish a
second transport layer connection with the server 106. In one case,
the appliance 200 provides an SSL VPN session to the client via the
first transport layer connection. In some embodiments, the
appliance 200 may already have an established connection with a
server. For example, the appliance 200 may have one or more pooled
transport layer connections to the server 106. In some cases, the
client agent 120 transmits a configuration command, e.g., /cfg, to
request and establish a SSL VPN session.
[0273] The appliance 200 may assign or otherwise provide the user
identified with the SSL VPN session with an IIP address 282. The
appliance 200 may use any of the systems and methods described
herein to assign the IIP address, such as any of the embodiments
described in conjunction with FIG. 4 and FIG. 5 above. The
appliance 200 may assign an IIP address 282 to a user from a
plurality of IIP addresses based on policy, temporal and/or status
information. For example, the appliance 200 may assign to the SSL
VPN session a most recently or most frequently used IIP address
282. The appliance 200, such as via session manager 915, maintains
the state of the IIP addresses 282 used or assigned to the user.
For example, the IIP address assigned to the user may be identified
as in the active state. The appliance 200 may also track any
temporal and client information associated with the user assigned
IIP address.
[0274] Further to step 1005, the appliance 200 may associate,
inherit or otherwise apply one or more policies to the SSL VPN
session, such as via session manager 915. In one embodiment, the
appliance 200 associates or inherits one or more policies with the
SSL VPN session based on the configuration of the policy engine 236
at the time of the request and/or establishment. In another
embodiments, the appliance associates or inherits one or more
policies with the SSL VPN session based on executed policy or
policy configuration commands upon the establishment of the SSL VPN
session, or any time thereafter.
[0275] The appliance 200, such as via session manager 915, may
store and maintain information on the established SSL VPN session
in one or more objects, data structures tables and/or files. Some
portions of the session information may be static. For example, the
session information is stored upon establishment and not changed
thereafter. In some cases, portions of the session information may
be dynamic. For example, the session manager 915 may store and
maintain counters for auditing and/or to hold statistics on the
session, such as bytes sent/received and transfer rates. In some
embodiments, the appliance 200, such as via session manager 915,
stores session information in a hash table. For example, a session
cookie may be hashed or used as a key to obtain information on a
session in a table.
[0276] At step 1010, the primary appliance 200 propagates
information on the SSL VPN session and/or IIP addresses to the
secondary appliance 200'. The primary appliance 200 may transmit or
communicate via the failover connection 930 to the secondary
appliance 200' to provide any information on the SSL VPN session,
IIP address used for the session and/or IIP addresses of the user.
The primary appliance 200 may communicate, marshal or otherwise
transfer the data from the one or more objects, data structures or
files to store and/or maintain the session and/or IIP address
information.
[0277] The primary appliance 200 may propagate the SSL VPN and/or
IIP address information at any time upon establishment of the
session or any time thereafter. In one embodiment, the primary
appliance 200 propagates the SSL VPN and/or IIP address information
in an synchronous manner. For example, upon establishment of the
SSL VPN session by the primary appliance, the appliance 200
propagates the information to the secondary appliance 200'. In one
embodiment, the primary appliance 200 propagates the information to
the secondary appliance after the receipt of the configuration
command, e.g., /cfg command, from the client agent requesting
establishment of the SSL VPN session. In other embodiments, the
primary appliance 200 propagates the SSL VPN and/or IIP address
information in a asynchronous manner. For example, the primary
appliance 200 may propagate the information based on a timeout
loop.
[0278] The primary appliance 200 may propagate SSL VPN and/or IIP
address information for each session, asynchronously or
synchronously. In some cases, the primary appliance 200 propagates
SSL VPN and/or IIP address information for multiple sessions. In
one embodiment, the propagation of multiple sessions and/or IIP
address information may occur subsequently to each other. In other
embodiments, the propagation of multiple session and/or IIP address
information may transmitted concurrently via one or more
connections 930. In one case, the propagation of multiple session
and/or IIP address information is multiplexed over a single
connection 930.
[0279] The primary appliance 200 may propagate any static session
and/or IIP address information once upon or after establishment of
the SSL VPN session and/or user assigned IIP address. The primary
appliance 200 may propagate any dynamically changed session and/or
IIP address information upon any changes to the session or IIP
address information. In another case, the primary appliance 200 may
propagate any dynamically changed session and/or IIP address
information upon a predetermined frequency or configured
events.
[0280] Upon receipt of any propagated information from the primary
appliance 200, the secondary appliance 200' may store the
propagated information in any type and form of objects, data
structures, tables and/or files. The session manager 915 may
establish the SSL VPN session on the secondary appliance 200. The
session manager 915 may identify the session as not active. For
example, the session manager 915 may put the backup or failover
session on hold. The session manager 915 may also establish one or
more IIP addresses for a user based on the propagated information.
The session manager 915 may maintain the states of the IIP
addresses based on the activity of the primary or secondary
appliance and session of the user. For example, the session manager
915 may identify the propagated IIP address as on hold. In another
example, the appliance 200' marks or identifies all the secondary
IIP addresses on hold or inactive. In one embodiment, the session
manager 915 activates an SSL VPN session and/or IIP address of a
user based on detection of a failover condition from the failover
detector.
[0281] At step 1015, the primary appliance 200 is detected in a
state or condition to cause failover. The failover detector 920 may
detect a failover condition of the primary appliance 200'. The
failover detector 920 may monitor the state or condition of the
primary appliance 200 on a predetermined frequency. In other cases,
the failover detector 920 mat monitor the state or condition of the
primary appliance 200 based on predetermined events. In one
embodiment, the client agent 120 informs the failover detector 920
and/or secondary appliance 200' of the state or condition of the
appliance 200. In another embodiment, the primary appliance 200,
such as via a first failover detector, informs a second failover
detector 920 and/or secondary appliance 200' of the state or
condition of the appliance 200.
[0282] The failover condition of the primary appliance 200 may be
for one or more SSL VPN sessions or for all sessions. In one
embodiment, the primary appliance 200 may be in a failover state or
condition with respect to a first SSL VPN session. In another
embodiment, the primary appliance 200 may remain active and/or
operations for a second SSL VPN session. For example, a first VIP
server 275 of the primary appliance 200 may go down while a second
VIP server 275 remains active. As such, the secondary appliance 200
may provide backup or failover to all the sessions of the primary
appliance or a portion of the sessions. In other embodiments, a
second backup appliance 200'' may provide failover services to
another portion of the sessions of the primary appliance 200.
[0283] Upon detection of the failover condition, the secondary
appliance 200 may change a state of any of the backup or failover
sessions. For example, the session manger 415 may activate one or
more sessions, such as a session propagated from the primary
appliance 200. The secondary appliance 200 may change the state of
any IIP addresses. For example, the session manager 915 may
activate one or more IIP addresses. In some embodiments, the
secondary appliance 200' changes the state of any session and/or
IIP address upon request to establish a session via the secondary
appliance 200'.
[0284] The appliance 200, 200' may use any type and form of address
resolution protocol (ARP) to resolve any IIP addresses. In one
embodiment, the appliance 200, 200' uses a gratuitous ARP to
resolve IIP addresses used by appliances. The appliance may
transmit an ARP or gratuitous ARP request on a predetermined time
period or frequency. The appliance may transmit an ARP or
gratuitous ARP request based on a detection event of the failover
detector 920. In some embodiments, the appliance transmit san ARP
or gratuitous ARP request based any type and form of scheduling
algorithm such as a staggered yield CPU algorithm. Based on the
results of the ARP requests, the appliance may activate one or more
IIP addresses.
[0285] At step 1020, the client establishes or obtains SSL VPN
session connectivity via the secondary appliance 200'. In one
embodiment, the client agent 120 detects or otherwise determines
the primary appliance 200 is not operational or otherwise no longer
servicing or providing the session. The client 120 is configured
and constructed to transmit a request to the secondary appliance
200' to establish or re-establish the session. In some embodiments,
the client agent re-establishes the connection and/or session using
a host name or an IP address of the primary appliance. With the
failover detected, the secondary appliance 200' may listen and
respond to the IP address or host name. In another embodiment, the
failover detector 920 or secondary appliance 200' informs the
client agent 120 to use the secondary appliance 200' to continue or
re-establish the session with the secondary appliance 200'. In yet
another embodiment, the client and/or client agent continues to use
the session after failover. The secondary appliance 200' seamlessly
and/or transparently continues to provide or resume the
session.
[0286] At step 1025, the secondary appliance 200' assigns to the
user for the SSL VPN session an IIP address assigned to the user,
such as the IIP address assigned during the SSL VPN session
provided by the primary appliance 200. The appliance 200' provides
IIP "stickiness" for the user during the failover as the session is
provided by the backup or secondary appliance 200'. The appliance
200' may use any of the systems and methods described in
conjunction FIGS. 4 and 5 to assign or designate IIP addresses to a
user or client based on the propagated IIP address information
received from the primary appliance 200.
[0287] In some cases, the secondary appliance may assign to the
user or client a most recently used IIP address. In another cases,
the secondary appliance may assign to the user or client a least
recently used IIP address. In some embodiments, the secondary
appliance assigns to the user or client the most used or one of the
most used IIP addresses of the user or client. In some embodiments,
the secondary appliance determines the propagated IIP address to
assign to the user or client responsive to one or more policies of
a policy engine. The secondary appliance may choose an inactive IIP
address and make the IIP address active for assigning to the user
or client. The second appliance may responsive to a policy specify
a domain name suffix to append to an identifier of the user to
provide a user domain name for the IIP address.
[0288] Referring now to FIG. 10B, an embodiment of example IIP
propagation scenarios during session failover are depicted. In some
cases, the "stickiness" of IIP addresses of a user may become out
of sync due to SSL VPN session deletion propagation failure. For
example, the IIP address "stickiness" may not be maintained in the
primary appliances but exists in the secondary appliance. The
appliance 200 includes a restoration mechanism 945 to restore the
appropriate IIP address stickiness in such situations.
[0289] In view of Example 1 of FIG. 10B, the system may include two
authenticated, authorized and audited users u1 and u2. These users
may be associated or bound to a group "g". Group g may have one IIP
address bound or associated with it. Initially, the users u1 and u2
may not have an IIP address bound to the user. In following the
transaction of the Example 1 diagram, the user u1 at T1 may
establish a SSL VPN session with the primary and be assigned the
IIP address of the group. Using the techniques described herein,
the SSL VPN session and IIP address is propagated at T1 from the
primary appliance to the secondary appliance. The user may logout,
disconnect or otherwise terminate the session in the primary
appliance 200. The primary appliance 200 may delete the session
also at T2. The propagation of the deleted session may fail at T2
leaving the secondary appliance 200' having the propagated first
session of the user and associated IIP address. At this point, the
secondary and primary appliances are out of synch with respect to
the SSL VPN session and/or the IIP address. At T3, the user logins
into the primary appliance and gets the same IIP address, and the
session and IIP address information is propagated to the secondary
appliance.
[0290] In view of the above example and in one embodiment, the
restorer 945 determines the out of sync states of the session
and/or IIP address between the secondary and primary appliance. The
restorer 945 may deleted the earlier session propagated at T1 and
restore the appropriate stickiness. For example, the restore 945
may delete the IIP address from the secondary appliance. In another
example, the restorer 945 may change the state of the IIP address
from active to inactive or some other non active state
designator.
[0291] In another Example of Example 2 depicted in FIG. 10B, the
user u1 establishes, at T1, a session with the primary appliance
200 and is assigned a IIP address. At T1, the primary appliance 200
propagates the session and IIP address information to the secondary
appliance 200'. At T2, the user u1 may log out. The propagation
from the primary appliance to secondary appliance may fail. For
example, the session of user u1 which was terminated may be deleted
by the primary appliance. At T3, the user u2 may establish or
re-establish a session with the primary appliance and reclaim or be
assigned the IIP address. The primary appliance may propagate to
the secondary appliance information on this session of u2 and the
assigned IIP address to u2. In one embodiment, the user u2 may
already be assigned the IIP address via the secondary. This may
create an IIP address conflict.
[0292] In view of this second example, the secondary appliance
and/or restorer 945 may determine if the propagated IIP address is
active in the secondary appliance. If the IIP address is active,
then either the session of u2 on the primary appliance or the
session of u2 on the secondary appliance may be deleted or
otherwise deactivated. Then the appliance having the remaining
session may reclaim and continue to use the IIP
I. End Point Reauthorization Upon Failover
[0293] Referring now to FIG. 11, an embodiment of steps of a method
for performing end point authorization or re-authorization during
appliance failover of an SSL VPN session is depicted. Using the
techniques discussed herein, the secondary appliance 200' performs
end point re-authorization on the client upon failover although the
client may have been authorized via the primary appliance 200. In
view of the systems and methods described herein in conjunction
with FIGS. 6A-6C, 7 and 8, the appliance 200 may use client
security strings to perform end point authorization. Via the values
of one or more client security strings, the appliance determines if
the client has attributes that meet a predetermined policy for
authorization. Depending on the values returned by the client via
client agent 120, the appliance 200 determined whether or not to
authorize the client to connect and establish an SSL VPN session
via the appliance.
[0294] As part of the session data and information, the appliance
200 such as via session manager may store, maintain or track the
values of the client security strings used to perform end point
detection and authorization. In some embodiments, these client
security string values or end point authorization values are not
propagated from the primary appliance to the secondary appliance.
In other embodiments, any client security string values propagated
to a secondary appliance may become out of sync or stale. In other
cases, the values for the client security strings would change if
re-obtained or detected from the client. For example, one or more
attributes or characteristics of the client may have changed
between the client's establishment of the session with the
appliance and the failover. The client may go through one or more
software upgrades or de-installs between SSL VPN session login and
the occurrence of a failover. The attributes of the client 102 may
be such that the values of the client security string may not allow
the client to be authorized in accordance with policy.
[0295] The embodiment of steps of method 1100 in FIG. 11 depict a
technique for end point detection and authorization to address the
issue with security during failover based on possible or actual
changes to client attributes that may impact client security
strings applied to the transferred session. In brief overview of
method 1100, at step 1105, the primary performs end point
authorization using client security strings and establishes an SSL
VPN session with a user. The user may be assigned an IIP address.
At step 1110, the primary appliance 200 propagates the SSL VPN
session information, including client security string expressions
to the secondary appliance 200'. At step 1115, a failover condition
of the primary appliance 200 is detected. At step 1120, the
secondary appliance 200' provides SSL VPN session to the client
based on propagated session information. At step 1125, the
secondary appliance places the transferred or failover SSL VPN
session on hold until end point detection and authorization is
performed on the client. At step 1130, the secondary appliance 200'
transmits the propagated client security string(s) to the client.
The client returns values for the client security strings. The
secondary appliance determines whether or not to authorized the
client for access to the network or server via the SSL VPN session.
At step 1135, if the client is authorized the secondary appliance
activates the SSL VPN session. Otherwise, the secondary appliance
maintains the session on hold, deactivates or otherwise deletes the
session.
[0296] In further details, at step 1105, an application or a user
on the client 102 may request a SSL VPN connection from a first
network 104 to a second network 104' such as to a server 106 on
network 104. As discussed above in connection with step 1005 of
FIG. 10A, the client agent 120 may establish a connection with the
primary appliance 200. The client agent 120 may transmit a request
to establish an SSL VPN session to a server or the network via the
appliance 200. The appliance 200 may associate, inherit or
otherwise apply one or more policies to the session or connection
request from the client, such as any type and form of end point
authorization policy. In response to the request, the appliance 200
in accordance with policy may perform any type and form of end
point detection and authorization. In some embodiments, the
appliance 200 performs any of the end point detection and
authorization techniques using client security strings described
above in connection with FIGS. 6A-6C, 7 and 8.
[0297] Using the client security string techniques described
herein, the appliance 200 based on policy transmits a client
security string for evaluation to the client agent 120. For
example, a client security string may in one embodiment be
expressed in the form of:
TABLE-US-00008 client.application[mcafeevirusscan].version >=
4.88 && client.svc[svchost]RUNNING
The client agent 120 evaluates the one or more client security
strings and transmits values for the strings to the appliance 200.
Based on the policy configuration, the appliance 200 determines
whether or not the client is authorized to establish the SSL VPN
session. If the client is authorized, the appliance 200 establishes
and allows the SSL VPN session to be used by the client 102.
Otherwise, the appliance 200 may deny or drop the client's request
for access via an SSL VPN session.
[0298] The appliance 200, such as via session manager 915, may
store and maintain information on the established SSL VPN session,
including any IIP address information, in one or more objects, data
structures tables and/or files. The appliance 200 may store and
maintain information on the client security strings applied to the
established SSL VPN session and any values thereof. In some
embodiments, the appliance 200 tracks the client security strings
used for the session via any pointing or indexing to the applicable
policies of the policy engine 236.
[0299] At step 1110, the primary appliance 200 propagates
information on the SSL VPN session and/or client security strings
to the secondary appliance 200'. The primary appliance 200 may
transmit or communicate via the failover connection 930 to the
secondary appliance 200' to provide any information on the SSL VPN
session, IIP addresses associated with the session and/or the
client security strings applied or used for the session. The
primary appliance 200 may communicate or transfer the data from the
one or more objects, data structures or files to store and/or
maintain the session and/or IIP address information.
[0300] The primary appliance 200 may propagate the SSL VPN and/or
client security string information at any time upon establishment
of the session or any time thereafter. In one embodiment, the
primary appliance 200 propagates the SSL VPN and/or client security
string information in an asynchronous manner. For example, upon
establishment of the SSL VPN session by the primary appliance, the
appliance 200 propagates the information to the secondary appliance
200'. In one embodiment, the primary appliance 200 propagates the
information to the secondary appliance after the receipt of the
configuration command, e.g., /cfg command, from the client agent
requesting establishment of the SSL VPN session. In other
embodiments, the primary appliance 200 propagates the SSL VPN
and/or or client security string information in an asynchronous
manner. For example, the primary appliance 200 may propagate the
information based on a timeout loop.
[0301] The primary appliance 200 may propagate SSL VPN and/or IIP
address information for each session, asynchronously or
synchronously. In some cases, the primary appliance 200 propagates
SSL VPN and/or or client security string information for multiple
sessions. In one embodiment, the propagation of multiple sessions
and/or IIP address information may occur subsequently to each
other. In other embodiments, the propagation of multiple session
and/or or client security string information may transmitted
concurrently via one or more connections 930. In one case, the
propagation of multiple session and/or IIP address information is
multiplexed over a single connection 930.
[0302] The primary appliance 200 may propagate any policies
including the client security strings to the secondary appliance.
The primary appliance 200 may propagate the policies to the
secondary appliance upon appliance startup, policy configuration or
binding of the policy to a user, session or other entity. In
another case, the primary appliance 200 may propagate any changed
client security string information upon a predetermined frequency
or configured events.
[0303] Upon receipt of any propagated information from the primary
appliance 200, the secondary appliance 200' may store the
propagated information in any type and form of objects, data
structures, tables and/or files. The session manager 915 may
establish the SSL VPN session on the secondary appliance 200. The
session manager 915 may identify the session as not active. For
example, the session manager 915 may put the backup or failover
session on hold. The session manager 915 may also associate the
propagated client string information for the session based on the
propagated information. In another embodiment, the secondary
appliance 200' inherits or associates the client security strings
from one or more policies of the policy engine 236 of the secondary
appliance 200' associated or bound to the session.
[0304] At step 1115, the primary appliance 200 is detected in a
state or condition to cause failover and at step 1120, the second
appliance provides SSL VPN session connectivity for the client. As
described in conjunction with FIG. 10A and steps 1015 and 1020, the
secondary appliance uses the propagated information to re-establish
an SSL VPN session for the client 102. For example, the client
agent 120 establishes the SSL VPN session with the secondary
appliance instead of the failed primary appliance. The secondary
appliance claims the transferred SSL VPN session and continues the
SSL VPN session for the client. In one embodiment, the user
requests to establish the SSL VPN session via another client.
[0305] At step 1125, the secondary appliance places or identifies
the transferred, propagated or established SSL VPN session as on
hold or otherwise not active or available for use. The secondary
appliance 200' may determine that the session has one or more end
point authorization policies or client security strings associated
with the session. In one embodiment, the secondary appliance 200'
determines the failed appliance 200 propagated client security
information for the session. In some embodiments, the secondary
appliance 200' determines to place the session on hold responsive
to a policy. In yet another embodiment, the secondary appliance
200' determines to place the session on hold based on the type of
client security string. In other embodiments, the secondary
appliance 200' determines to place the session on hold based on the
value of the client security string detected via the primary
appliance and propagated to the secondary appliance. In one
embodiment, the secondary appliance 200' automatically places the
SSL VPN session on hold until the client is re-authorized.
[0306] At step 1130, the secondary appliance performs end point
detection and authorization on the client for the transferred SSL
VPN session. In one embodiment, the secondary appliance transmits
the propagated client security string(s) to the client agent 120
for evaluation. In some embodiment, the secondary appliance
transmits to the client agent one client security string from a
plurality of propagated client security strings. In some cases, the
secondary appliance determines which of the propagated client
security strings to obtain updated values or to verify the values
from the client upon failover. In one case, the secondary appliance
may determine that is not required or desired to check the value of
a client security string after failover. For example, the secondary
appliance may determine the value of the client security string may
not have changed or is not likely to have changes.
[0307] In another embodiment, the secondary appliance transmits the
client security string from any inherited policies or polices bound
to the user or session. In some embodiments, the secondary
appliance transmits additional client security string in
conjunction with the propagated client security strings. In one
embodiment, the secondary appliance modifies one or more propagated
client security strings, or any portions thereof, by policy or
otherwise. In one embodiment, the secondary appliance combines the
propagated client security strings with one or more client security
strings imposed on the session by the secondary appliance via
policy or otherwise.
[0308] Further to step 1130, the secondary appliance receives from
the client agent 120 an evaluation of the one or more transmitted
client security strings. The secondary appliance checks, validates
or otherwise compares these values to acceptable values indicated
by one or more policies of the policy engine. The comparison to
values specified via policy determines whether or not the client is
authorized for access. The values of the client attributes
determined via evaluation of the client security string may or may
not be acceptable in accordance with policy. In another embodiment,
the result of evaluation of the client security string or series of
client security strings determines whether or not the client is
authorized for access. In some embodiments, the secondary appliance
200 performs evaluation of at least a portion of the expression of
a plurality of client security strings to determine authorization
of the client.
[0309] At step 1135, the secondary appliance 200 determines to
activate or not activate the transferred SSL VPN session based on
the results of end point detection and authorization of the client.
If after appliance failover, the client is re-authorized in
accordance with policy, such as via client security strings, the
secondary appliance activates the SSL VPN session put on hold. In
one embodiment, the session manager 915 responsive to the policy
engine and end point authorization changes the state of the SSL VPN
session to active. In another embodiment, the secondary appliance
re-authenticates the user in addition to authorizing the client.
The secondary appliance may activate the SSL VPN session based on
re-authentication of the user and re-authorization of the
client.
[0310] If after appliance failover, the client is not re-authorized
in accordance with policy, such as failing to provide acceptable
values for the client security strings, the secondary appliance
does not activate the SSL VPN session placed on hold. In one
embodiment, the secondary appliance, such as via session manager
915, maintains the SSL VPN session on hold. In another embodiment,
the secondary appliance, such as via session manager 915, changes
the state of the SSL VPN session to invalid, inactive or not
authorized. In some embodiments, the secondary appliance, such as
via session manager 915, deletes the SSL VPN session. In another
embodiment, the secondary appliance de-establishes the SSL VPN
session. In one embodiment, the secondary appliance drops or
disconnects the connection with the client responsive to the client
failing end point authorization. In some embodiments, the secondary
appliance activates the session but limits the user's access based
on the results of the end point detection, such as by placing the
user in a quarantined access group.
[0311] In view of the structure, functions and operations during
failover as described in FIGS. 9-11, the appliance may perform any
of the steps of method 1000 and method 1100 in any combination. As
such, in some embodiments, the appliance may provide both IIP
address "stickiness" for users during failover as well as end point
re-authorization. In this manner, the systems and method of the
appliance described herein provide a seamless and/or transparent
failover solution that provides continued and/or additional
security measures.
[0312] Many alterations and modifications may be made by those
having ordinary skill in the art without departing from the spirit
and scope of the invention. Therefore, it must be expressly
understood that the illustrated embodiments have been shown only
for the purposes of example and should not be taken as limiting the
invention, which is defined by the following claims. These claims
are to be read as including what they set forth literally and also
those equivalent elements which are insubstantially different, even
though not identical in other respects to what is shown and
described in the above illustrations.
* * * * *